FURVERT!

anthro anus bodily_fluids body_in_mouth canid canine canis duo extreme_size_difference head_first hybrid lagomorph leporid male male/male male_pred male_prey mammal mephitid nude rabbit saliva size_difference skunk skunkhase swallowing tail tongue vore wolf wolfenfury

ambiguous/ambiguous ambiguous_form ambiguous_gender ambiguous_pred ambiguous_prey anthro canid canine canis cutaway digital_media_(artwork) duo extreme_size_difference hybrid internal lagomorph leporid mammal mephitid oral_vore rabbit side_view size_difference skunk skunkhase solo_focus swallowing tail tongue vore wolf wolfenfury wolfenfury_(character)

almost_fully_inside ambiguous_gender ambiguous_prey anus balls bodily_fluids body_in_urethra body_outline breast_imprints breasts close-up cock_vore cocoa_(modeseven) dark_body dark_skin duo erection extreme_size_difference face_imprint feet_first foreskin foreskin_play front_view fully_inside genital_close-up genital_fluids genitals grandfathered_content grey_hair gynomorph gynomorph_pred hair head_first heart_reaction heart_symbol human human_only human_pred human_prey humanoid_genitalia humanoid_penis imprint in_mouth inside_balls inside_penis intersex intersex_pred larger_gynomorph larger_human larger_intersex larger_pred male male_prey mammal modeseven mother_(lore) multiple_prey nipples not_furry nude parent_(lore) partially_inside penetration penile penis penis_close-up precum size_difference smaller_ambiguous smaller_human smaller_male two_prey_at_once urethral urethral_bulge urethral_penetration vore vowelless vowelless_vocalization

anthro black_and_white body_in_urethra canid canine canis cock_vore comic duo erection extreme_size_difference eyes_closed faceless_character faceless_male fox genitals heart_symbol humanoid_genitalia humanoid_penis inside_penis lupine_assassin male male/male male_pred male_prey mammal michael_higgs micro monochrome pen_(artwork) penile penis simple_background size_difference tail traditional_media_(artwork) urethral_bulge vore white_background wolf

anthro black_and_white bodily_fluids canid canine canis cock_vore comic cum duo erection extreme_size_difference eyes_closed fox genital_fluids genitals humanoid_genitalia humanoid_penis inside_balls inside_penis internal lupine_assassin male male/male male_pred male_prey mammal michael_higgs micro monochrome open_mouth pen_(artwork) penile penis shaking simple_background size_difference tail traditional_media_(artwork) trembling urethral_bulge vein vore white_background wolf

anthro black_and_white bodily_fluids body_in_urethra canid canine canis cock_vore comic crying duo english_text erection extreme_size_difference fox genitals humanoid_genitalia humanoid_penis lupine_assassin male male/male male_pred male_prey mammal michael_higgs micro monochrome open_mouth pen_(artwork) penile penis simple_background size_difference tail tears teeth text tongue tongue_out traditional_media_(artwork) vore white_background wolf

2010 anthro anthro_pred aylia black_hair body_in_mouth breasts canid canine canis cleavage clothed clothing domestic_dog duo dweet-tea extreme_size_difference feet_first female female_pred gothyk green_eyes hair holding_on male mammal open_mouth oral_vore partially_inside piercing purple_eyes red_hair size_difference teasing tongue tongue_piercing tongue_stud vore whinry

anthro canid canine dialogue english_text extreme_size_difference feet fox group hindpaw internal larger_male male male/male male_pred male_prey mammal oliver_(rockk) paws procyonid raccoon rockk size_difference smaller_male tail text vore

amonomega anthro beverage blue_and_white canid canine canis clothing comic extreme_size_difference female food gaping_mouth group johnny_colossus kerchief lavender_steele lupine_assassin male male/male male_pred male_prey mammal monochrome mouth_shot open_mouth oral_vore simple_background size_difference sketch swallowing traditional_media_(artwork) unfinished uvula vore white_background wolf

3_toes 4_toes alessandra_(scream) anthro barefoot beach bikini black_hair blonde_hair blue_hair boat border_collie canid canine canis claws clothed clothing cloud collar collie day demicoeur digital_media_(artwork) digitigrade dipstick_tail domestic_dog extreme_size_difference feet female fox group hair herding_dog hindpaw karla_(karla) larger_anthro larger_female macro macro_anthro macro_female mammal markings nikita_(karla) outside pastoral_dog pawpads paws plantigrade seaside sheepdog size_difference skimpy sky smaller_anthro spiked_collar spikes swimwear tail tail_markings tight_clothing toe_claws toes tongue two-piece_swimsuit vehicle watercraft wolf

2010 3:4 5_fingers ailurid ambiguous_gender anthro anthro_pred black_ears black_nose blonde_hair blue_eyes bodily_fluids bottomwear breasts brown_hair chilli_dog cleavage cleavage_cutout clothed clothing cutout denim denim_bottomwear denim_clothing digital_media_(artwork) drooling duo ear_tuft extreme_size_difference eye_contact eyewear fan_character fangs female female/ambiguous female_on_anthro fingers food food_fetish food_play fur geckonori generation_1_pokemon glasses green_eyes hair hand_behind_back holding_food holding_object hot_dog imminent_vore jeans larger_anthro larger_female looking_at_another mammal micro multicolored_tail navel nintendo pants pikachu pink_ears pink_tail pokemon pokemon_(species) pokemorph red_cheeks red_panda rodent sabrina_(geckonori) saliva scared shirt short_hair size_difference smaller_ambiguous solo_focus sparky_the_chu_(character) tail teeth tongue tongue_out topwear tuft yellow_body yellow_ears yellow_fur zipper

2010 balls big_balls bodily_fluids canid canine canis city cum destruction digital_media_(artwork) duo erection extreme_size_difference fen_(character) feral genital_fluids genitals hyper macro male mammal penis phenris quadruped rampage size_difference solo_focus tail what wolf wolfen

abs ambiguous_gender anthro bdsm bodyjob bondage bound canid canine canis chain domestic_cat dominant erection extreme_size_difference eyes_closed felid feline felis genitals greyscale group group_sex hands_behind_head hug hugging_another hugging_another's_penis hugging_penis kit-cox larger_dom male mammal monochrome muscular oral penis pose rogue_(character) sex simple_background size_difference smile tail white_background wolf

1999 anthro bdsm bondage bound canid canine canis do_not_distribute dominant dominant_male duo english_text erection extreme_size_difference genitals hands_behind_head humanoid_genitalia humanoid_penis jeri_kleinlowe larger_dom larger_male male male/male mammal marker_(artwork) monochrome muscular penis rodent rogue_(character) size_difference smaller_male smile solo_focus spread_legs spreading submissive submissive_male tail text traditional_media_(artwork) wolf

2000 anthro bad_metadata black_and_white bodily_fluids collar crush cum destruction dominant ear_piercing erection extreme_size_difference ferris genital_fluids genitals group human humanoid_genitalia humanoid_penis jewelry larger_male macro male mammal masturbation missing_sample monochrome orgasm penile penile_masturbation penis piercing size_difference smile tail traditional_media_(artwork)

anthro comic duo english_text erection extreme_size_difference genitals graphite_(artwork) hi_res magic male male/male mammal michael_higgs micro monochrome mouse multiple_scenes murid murine penile penis penis_riding procyonid raccoon rodent shrinking simple_background size_difference size_transformation tail text traditional_media_(artwork) transformation white_background

anthro comic duo erection extreme_size_difference genitals graphite_(artwork) hi_res humanoid_genitalia humanoid_penis male male/male mammal masturbation michael_higgs micro monochrome mouse multiple_scenes murid murine penile penile_masturbation penis procyonid raccoon rodent shrinking simple_background size_difference size_transformation tail traditional_media_(artwork) transformation white_background

2010 anthro balls canid canine erection extreme_size_difference faceless_character faceless_male fox frottage genitals graphite_(artwork) greyscale group hi_res larger_male male male/male mammal michael_higgs monochrome mouse murid murine penile penis penises_touching rodent sex simple_background size_difference sketch smaller_male tail text traditional_media_(artwork) white_background

2004 4:5 anthro balls canid canine canis duo extreme_size_difference fox genitals lying macro male mammal nude on_back plant plantigrade size_difference standing tail taurin_fox tree wolf wood

anthro canid canine canis comic directional_arrow disc_jockey duo extreme_size_difference green_eyes kerchief larger_male lupine_assassin male male/male male_pred male_prey mammal mouth_shot open_mouth oral_vore size_difference smaller_male square_crossover swallowing tail tan_(artist) time_paradox tongue vore wolf

age_difference anthro aquatic arthropod big_breasts breasts butt cetacean clothed clothed_anthro clothed_male clothing copepod crab crustacean cunnilingus daughter_(lore) decapod drawn-sex extreme_size_difference father_(lore) father_and_child_(lore) father_and_daughter_(lore) female female_anthro flower flower_cloud_(spongebob) genitals group interspecies larger_anthro larger_child larger_female larger_nude malacostracan male male/female male_anthro mammal maxillopod micro mr._krabs nickelodeon nipples nude older_anthro older_male on_model oral parent_(lore) parent_and_child_(lore) parent_and_daughter_(lore) pearl_krabs physeteroid plankton_(species) plant public public_sex sea_sponge sex sheldon_j._plankton shocked size_difference smaller_anthro smaller_male sperm_whale spongebob_squarepants spongebob_squarepants_(character) spread_legs spreading the_krusty_krab toothed_whale vaginal vulva whale younger_anthro younger_female younger_male

anthro big_breasts bodily_fluids breasts canid canine canis comic duo english_text erection extreme_size_difference factory female genitals graphite_(artwork) growth hi_res huge_breasts humanoid_genitalia humanoid_penis hyper lactating male mammal michael_higgs milk monochrome muscular nipples nude orgasm penis projectile_lactation shrinking simple_background size_difference size_transformation tail text traditional_media_(artwork) transformation transformation_through_milk white_background wolf

anthro balls_expansion big_breasts big_penis body_size_growth breasts canid canine canis comic duo english_text erection expansion extreme_size_difference factory female genital_expansion genitals graphite_(artwork) growth hi_res huge_breasts huge_penis humanoid_genitalia humanoid_penis hyper hyper_genitalia hyper_penis male mammal michael_higgs milk monochrome muscular nipples nude orgasm penis penis_expansion simple_background size_difference size_transformation tail text traditional_media_(artwork) transformation white_background wolf

anthro big_breasts big_penis breasts canid canine canis comic duo erection extreme_size_difference factory female genitals graphite_(artwork) growth hi_res huge_breasts huge_penis hyper male mammal michael_higgs milk monochrome muscular nipples nude orgasm penis simple_background size_difference small_head solo_focus tiny_head traditional_media_(artwork) white_background wolf

anthro big_breasts body_size_growth breasts canid canine canis comic destruction duo english_text erection extreme_size_difference eyes_closed factory female genitals graphite_(artwork) growth hi_res huge_breasts hyper macro male mammal michael_higgs milk monochrome muscle_growth muscular nipples nude penis size_difference size_transformation small_head solo_focus tail text tiny_head traditional_media_(artwork) transformation wolf

anthro big_breasts body_size_growth breasts canid canine canis comic destruction duo english_text erection extreme_size_difference eyes_closed factory female genitals graphite_(artwork) growth hi_res huge_breasts hyper macro male mammal michael_higgs milk monochrome muscle_growth muscular nipples nude penis size_difference size_transformation small_head solo_focus tail text tiny_head traditional_media_(artwork) transformation wolf

absorption_vore anthro attribute_theft biceps big_breasts big_muscles body_size_growth breasts canid canine canis city comic destruction energy_drain english_text extreme_size_difference eyes_closed factory female genitals graphite_(artwork) group growth hi_res high-angle_view huge_breasts huge_muscles hyper hyper_muscles landscape_dwarfing larger_female macro male mammal michael_higgs monochrome muscle_growth muscular muscular_female nipples penis scared shrinking size_difference size_theft size_transformation smaller_female smaller_male tail text traditional_media_(artwork) transformation vore wolf

alien breasts comic earthbound_(series) extreme_size_difference female genitals giygas group hi_res human humanoid kalnareff male mammal nintendo nipples non-mammal_nipples nude size_difference tail unbirthing vaginal vore vulva

alien ball breasts comic duo earthbound_(series) extreme_size_difference female genitals giygas hi_res human humanoid humanoid_genitalia humanoid_penis kalnareff male mammal nintendo nipples non-mammal_nipples nude penis size_difference tail unbirthing vaginal vore vulva

alien bladder blue_body blue_insides blue_skin blue_vulva bodily_fluids breasts camel_toe clothed clothing comic cross_section dialogue duo earthbound_(series) english_text extreme_size_difference female genital_fluids genitals giygas hi_res human humanoid internal internal_anal internal_vaginal kalnareff male mammal navel nintendo nipples non-mammal_nipples nude organs panties panties_only size_difference tail text topless unbirthing underwear underwear_only uterus vaginal vaginal_fluids vore vulva

alien anus blue_anus blue_body blue_insides blue_nipples blue_skin blue_vulva bodily_fluids breasts butt clitoral clothed clothing comic duo earthbound_(series) extreme_size_difference female fingering genital_fluids genitals giygas hi_res human humanoid internal internal_vaginal kalnareff leaking male mammal navel nintendo nipples non-mammal_nipples nude panties panties_only pussy_juice_leaking raised_leg size_difference tail teeth topless unbirthing underwear underwear_only urethra vaginal vaginal_fingering vaginal_fluids vaginal_fluids_on_butt vaginal_fluids_on_hand vore vulva

alien backsack balls blue_body blue_nipples blue_skin blue_vulva bodily_fluids breasts butt camel_toe clothed clothing comic dialogue digital_media_(artwork) duo earthbound_(series) english_text extreme_size_difference female genital_fluids genitals giygas hi_res human humanoid internal internal_vaginal kalnareff male mammal nintendo nipples non-mammal_nipples nude open_mouth panties panties_only size_difference speech_bubble spread_legs spreading teeth text topless unbirthing underwear underwear_only vaginal vaginal_fluids vore vulva

2010 anal anal_foot_gulp anal_penetration anal_vore anthro anus apoclysia belly breasts butt city demon extreme_size_difference female food genitals group humanoid kalnareff lizard macro male non-mammal_breasts obese overweight penetration prehensile_tail reptile scalie size_difference slightly_chubby slightly_chubby_anthro slightly_chubby_female slightly_chubby_male swallowing tail tongue tongue_out unbirthing vaginal vore vulva

2010 anal anal_penetration anal_vore anus apoclysia belly bodily_fluids body_inside_body breasts butt cutaway demon extreme_size_difference eyes_closed female genital_fluids group humanoid inflation internal internal_anal internal_vaginal kalnareff lactating lizard macro male masturbation nipples non-mammal_breasts non-mammal_nipples open_mouth palate penetration reptile scalie size_difference swallowing tail tongue unbirthing vaginal vaginal_fluids vore what

2009 armor dragon duo extreme_size_difference feral fire headgear helmet horn lava macro male melee_weapon mythological_creature mythological_scalie mythology nejita open_mouth scalie size_difference sword tail teeth warm_colors warrior weapon

2010 abdominal_bulge anal anal_penetration anal_vore anthro anthrofied big_breasts bodily_fluids breast_bulge breast_milking breast_vore breasts bulge butt charem charmeleon digital_media_(artwork) dragon duo extreme_size_difference fan_character female female_penetrated fur furred_dragon furred_scalie gecko generation_1_pokemon huge_breasts kalnareff lactating lizard male male/female male_penetrating male_penetrating_female milk multiple_prey mythological_creature mythological_scalie mythology nintendo nipple_fetish nipple_play nipple_vore nipples non-mammal_breasts non-mammal_nipples open_mouth oral_vore paws penetration pokemon pokemon_(species) pokemorph reptile scalie sex size_difference tail tieldraggy tongue unusual_vore vergel vore

1:1 2007 2_penises 5_fingers 5_toes 6_breasts abstract_background anthro anthro_on_anthro areola artist_name balls bell bell_collar big_balls big_breasts big_penis biped black_claws black_horn black_penis black_wings blue_body blue_breasts blue_face blue_feet blue_fur blue_hair blue_tail blue_wings bodily_fluids breasts claws collar collar_only cum cum_covered cum_on_balls cum_on_body cum_on_breasts cum_on_leg cum_on_penis cum_on_self dragon duo erection extreme_size_difference eye_contact feet felid fellatio fingers fur genital_fluids genitals green_background gynomorph gynomorph/gynomorph hair half-erect horn huge_balls huge_breasts huge_penis hyper hyper_genitalia hyper_penis intersex intersex/intersex interspecies larger_gynomorph larger_intersex licking long_hair looking_at_another mammal membrane_(anatomy) membranous_wings messy monotone_breasts monotone_face monotone_genitals monotone_hair monotone_penis monotone_tail multi_breast multi_genitalia multi_penis multicolored_wings mythological_creature mythological_scalie mythology nipples non-mammal_balls non-mammal_breasts non-mammal_nipples nude oral orange_balls orange_body orange_breasts orange_face orange_tail orange_wings penile penis penis_size_difference pink_areola pink_hair pink_nipples purple_collar purple_penis purple_tongue purple_wings scalie sex signature simple_background size_difference smaller_gynomorph smaller_intersex smile snout sukebepanda tail text toes tongue tongue_out vein veiny_penis wings year yellow_eyes

ambiguous_gender ambiguous_prey anthro bird's-eye_view blue_sclera brown_hair camera canid canine canis chest_tuft extreme_size_difference fangs farorenightclaw fur gaping_mouth grey_body grey_fur group hair high-angle_view imminent_vore larger_male long_tongue male male/ambiguous male_pred mammal mouth_shot open_mouth sharp_teeth size_difference tail teeth throat tongue tongue_out tuft vore white_body white_fur wolf

2006 anthro big_breasts biped black_eyes bodily_fluids breasts ceratopsian ceratopsid chasmosaurine clothing dinosaur duo english_text extreme_size_difference facial_horn female footwear gloves handwear horn huge_breasts lex_cypher marginocephalian mask navel nipples non-mammal_breasts non-mammal_nipples nose_horn open_mouth ornithischian pink_nipples prehistoric_species reptile rope scalie shoes size_difference sweat sweatdrop tail text tongue triceratops

3:4 animal_humanoid big_butt blue_eyes bra breasts brown_hair butt cat_humanoid circlet clothing duo ear_tuft egyptian extreme_size_difference felid felid_humanoid feline feline_humanoid female fur hair human humanoid inner_ear_fluff jewelry kneeling larger_humanoid lens_flare macro mammal mammal_humanoid mythological_creature mythological_sphinx mythology pyramid sand size_difference smaller_human solo_focus sun tail tuft underwear unknown_artist wide_hips

2010 ambiguous_gender anthro black_body black_eyes black_fur blue_body blue_eyes blue_fur canid canine crossover dark_theme digital_media_(artwork) duo esepibe extreme_size_difference fur generation_4_pokemon hi_res humanoid japan_studio_(game_developer) legendary_pokemon lucario mammal nintendo pokemon pokemon_(species) red_eyes regigigas shadow_of_the_colossus size_difference sony_corporation sony_interactive_entertainment tail team_ico_(game_developer) yellow_body yellow_fur

akaitera aquatic blastoise blue_body blue_skin charizard cosmic_horror creepypasta detailed dragon elemental_creature european_mythology extreme_size_difference feral flora_fauna fur generation_1_pokemon group human lapras lovecraftian_(genre) macro male mammal membrane_(anatomy) membranous_wings mythological_creature mythological_scalie mythology nightmare_fuel nintendo pikachu plant pokemon pokemon_(species) pokemon_trainer pose realistic red_(pokemon) red_eyes reptile rodent scalie simple_background size_difference smaller_human snorlax starter_trio tail team_pose toony venusaur western_dragon white_background wings yellow_body yellow_fur yoshio_(artist) zalgo_(creepypasta)

2010 absurd_res all_fours anal anal_penetration anthro anthro_on_anthro anthro_on_feral anthro_penetrated anthro_penetrating anthro_penetrating_anthro arson artie axe balls bestiality bodily_fluids butt canid canine canis chain collaborative collaborative_handjob collaborative_sex collar cum cum_in_ass cum_in_mouth cum_inside cum_on_butt cum_on_face cum_on_ground cum_on_tongue cumshot digital_media_(artwork) dipstick_tail doggystyle domestic_dog dominant dominant_anthro dominant_feral dominant_male dragon ejaculation erection extreme_size_difference eyes_closed fangs fellatio feral feral_on_top fire flaccid forced fox from_behind_position genital_fluids genitals group group_sex handjob hi_res humanoid_genitalia humanoid_penis interspecies large_penetration larger_anthro larger_dom larger_feral larger_male leash leash_pull looking_pleasured male male/male male_anthro male_feral male_penetrated male_penetrating male_penetrating_male male_rape male_raped male_raping_male mammal markings mass_rape melee_weapon messy mount muscular muscular_male mythological_creature mythological_scalie mythology nude open_mouth oral orgasm orgasm_face orgy outside penetration penile penile_penetration penis penis_milking penis_size_difference pillage rape saddle scalie service_height servicing_from_below sex size_difference smaller_anthro smaller_male smaller_penetrated spitroast submissive submissive_anthro submissive_male tail tail_markings tattoo teeth tephros threesome tongue trio war weapon wingless_dragon zaush

2010 absurd_res all_fours alpha_channel anal anthro anthro_on_anthro anthro_on_feral anthro_penetrated anthro_penetrating anthro_penetrating_anthro anthro_raping_anthro axe balls_deep bestiality bodily_fluids canid canine canis chain cum cum_in_ass cum_inside cumshot digital_media_(artwork) dipstick_tail doggystyle domestic_dog dominant dominant_anthro dominant_feral dominant_male dragon ejaculation erection extreme_size_difference eyes_closed fangs feral feral_on_top flaccid forced fox from_behind_position genital_fluids genitals group group_sex hi_res humanoid_genitalia humanoid_penis interspecies larger_anthro larger_feral larger_male looking_pleasured male male/male male_anthro male_feral male_penetrated male_penetrating male_penetrating_male male_rape male_raped male_raping_male mammal markings melee_weapon mount muscular muscular_male mythological_creature mythological_scalie mythology open_mouth oral orgasm orgasm_face orgy penetration penis rape scalie service_height servicing_from_below sex simple_background size_difference smaller_anthro smaller_male smaller_penetrated submissive submissive_anthro submissive_male tail tail_markings tattoo teeth tephros third-party_edit threesome tongue tongue_out transparent_background trio weapon zaush

anthro anthrofied aquarium aquatic behind_glass breasts cetacean english_text extreme_size_difference female group janner3d larger_female macro mammal masturbation nude physeteroid public_aquarium size_difference solo_focus sperm_whale straddling tail text thalassophobia_cure toothed_whale tunnel underwater vaginal vaginal_masturbation vivarium water whale

2000 anchor anthro big_breasts breasts dragon duo extreme_size_difference eye_contact female graphite_(artwork) ken_cougr_(character) kencougr larger_female looking_at_another macro male monochrome mythological_creature mythological_scalie mythology nipples non-mammal_breasts non-mammal_nipples pathia scalie signature size_difference smaller_male spread_legs spreading tail tail_motion tailwag traditional_media_(artwork)

brown_hair chainsaw city destruction digital_media_(artwork) dragon duo dutch_angle extreme_size_difference female feral hair hi_res human macro mammal mythological_creature mythological_scalie mythology nikerabi power_tool scalie size_difference tail tools wings

2010 anthro bed bed_sheet bedding black_penis bloodhound_(artist) bodily_fluids canid canine canis clitoris digital_media_(artwork) domestic_dog duo erection extreme_size_difference eyes_closed female fisting fox furniture genital_fluids genitals humanoid_genitalia humanoid_penis humanoid_vulva large_female lying male male/female mammal micro nik_(sonicfox) nude on_back penetration penis precum sex size_difference sleep_sex sleeping smaller_male tail vaginal vaginal_fisting vaginal_penetration vulva

anthro biceps big_breasts big_muscles body_size_growth breasts canid canine canis city comic destruction duo erection explosion extreme_size_difference eyes_closed factory female female_focus genitals giga graphite_(artwork) growth hi_res huge_breasts huge_muscles humanoid_genitalia humanoid_penis hyper hyper_breasts hyper_muscles macro male mammal michael_higgs monochrome moon muscle_growth muscular muscular_female nipples nuclear_power_plant penis planet scared size_difference size_transformation solo_focus space terra_macro traditional_media_(artwork) transformation what what_has_science_done wolf

2008 anthro bodily_fluids canid canine canis crux_(artist) cum domestic_cat domestic_dog duo erection extreme_size_difference eye_contact felid feline felis genital_fluids genitals grin hybrid larger_male licking looking_at_another male male/male male_penetrated male_penetrating male_penetrating_male mammal monochrome nervous oral penetration penile penis penis_lick sex size_difference smaller_male smile tail tongue tongue_out wolf