FURVERT!

4_toes 5_fingers accessory anthro badger ballbusting black_and_white bottomwear bulge canid canine canis castration cigarette clothed clothing cock_and_ball_torture detailed_bulge duo erection feet fingers fo foot_on_balls footwear forced forced_castration genital_mutilation genital_outline genital_torture genitals hat headgear headwear humanoid_genitalia humanoid_penis male mammal mobster monochrome mustelid musteline mutilation necktie pain pants penis penis_outline scarf shoes shorts simple_background smoke smoking suit tail toes topless underwear unwanted_erection white_background wolf wolfblade

4_fingers 5_fingers anthro avian bird bishamon blue_body blue_fur bottomwear brown_nose cammy_white canid canine canis capcom clothing clover_studio darkstalkers disney fa_mulan_(disney) female feral fingers front_view fur goofy_(disney) green_clothing grey_body grey_fur group haplorhine helen_parr human jon_talbain light_body light_skin living_armor m._bison male maleficent mammal mandrill marvel mega_man_(character) mega_man_(series) mickey_mouse monkey mouse mulan_(1998) murid murine muscular muscular_human muscular_male mythological_canine mythological_creature mythology old_world_monkey open_mouth orange_clothing orange_shirt orange_topwear pants pete_(disney) pixar primate purple_body purple_skin rafiki red_clothing rodent ryu_(street_fighter) sagat samurai shirt side_view skinny skinny_anthro skinny_female skinny_human skinny_male sleeping_beauty_(1959) slim slim_female slim_human snout street_fighter tan_body tan_skin the_incredibles the_lion_king topwear unknown_artist vega viewtiful_joe viewtiful_joe_(series) warrior werecanid werecanine werecreature werewolf white_bottomwear white_clothing white_pants white_shirt white_topwear wolf yellow_body yellow_fur yellow_skin zangief

anthro bear black_and_white bottomwear cigar clothed clothing lolverine male mammal monochrome muscular muscular_anthro muscular_male one_eye_closed pants pose simple_background sketch smoke smoking solo topless white_background wink

1:1 5_fingers abs beard black_and_white bottomwear braided_beard character_name clothed clothing demon ear_piercing facial_hair fingers fur hair hi_res horn ishigray male monochrome pants piercing rokku simple_background sketch solo text topless tusks white_background

2011 anthro blue_and_white bottomwear breasts canid canine cleavage clothed clothing clothing_around_legs digital_drawing_(artwork) digital_media_(artwork) female fox mammal miniskirt monochrome panties panties_around_legs panties_below_skirt panties_down partially_clothed shirt simple_background sketch skipsy skirt solo tail thong topwear underwear underwear_around_legs underwear_down white_background

4_toes 5_fingers anthro barefoot biped black_and_white bottomwear clothed clothed_anthro clothed_male clothing digitigrade feet fingers fully_clothed fur hair humanoid_hands jax_endsleigh line_art looking_at_viewer male male_anthro mammal mephitid monochrome on_one_leg open_mouth open_smile pants simple_background skunk smile solo standing tail text toes url watermark white_background zareonianwolf

2011 ailurid anthro anthro_on_anthro armwear belly big_belly big_breasts black_clothing black_topwear blush bodily_fluids bone_frill bottomwear bottomwear_down breasts bridal_lingerie bride ceratopsian ceratopsid chasmosaurine cigar clothed clothing cum cum_in_mouth cum_inside digital_media_(artwork) dinosaur dreadlocks duo ear_piercing erection fellatio female female_penetrated fingerless_gloves fishnet_clothing fishnet_handwear footwear frill_(anatomy) garter_belt garter_straps genital_fluids genitals gloves grey_bottomwear grey_clothing grey_outerwear handwear jacket legwear lingerie male male/female male_penetrating male_penetrating_female mammal marginocephalian nude oral oral_penetration ornithischian overweight pants pants_down partially_clothed pattern_bottomwear pattern_clothing penetration penile penis pentaceratops piercing pregnant prehistoric_species red_panda reptile scalie sex shirt side_boob slightly_chubby smoke smoking socks striped_bottomwear striped_clothing stripes suit tail thick_penis thigh_highs thigh_socks topless topwear warm_colors white_armwear white_bottomwear white_clothing white_legwear wolfy-nail

2010 4_fingers american_flag anthro batman_(series) blue_body blue_skin border bottomwear bulbous_nose captain_america catwoman city cityscape clothing container cosplay crossover crossover_cosplay currency_symbol dc_comics digital_media_(artwork) disney dollar_sign english_text fingers footwear front_view graffiti group hi_res holding_container holding_object holding_shield male mammal marvel mickey_mouse mouse multicolored_bottomwear multicolored_clothing multicolored_shorts murid murine pattern_bottomwear pattern_clothing pattern_shorts red_bottomwear red_clothing red_shorts restricted_palette rodent satire shield shoes shorts solo_focus speedy_graphito spray_can standing striped_bottomwear striped_clothing striped_shorts stripes symbol text two_tone_bottomwear two_tone_clothing two_tone_shorts united_states_of_america white_border white_bottomwear white_clothing white_footwear white_shoes white_shorts

anthro belly big_belly big_breasts blue_and_white bottomwear breasts clothed clothing female footwear hi_res lachland-nightingale leaning leaning_backward line_art mammal monochrome mouse murid murine pregnant reclining rodent sandals shoes shorts solo tail unbuttoned

2011 3_fingers 4_toes aircraft airplane anthro anuv athletic athletic_male beach biped black_and_white bottomwear bracelet bulge canid canine claws clothing cloud comic crash crop_top detailed_background dipstick_tail ear_piercing ear_ring eyewear feet finger_claws fingers fox genie glasses grass hair hand_on_cheek hi_res jewelry lamp leg_warmers legwear lost magic magic_lamp male mammal markings monochrome multicolored_tail navel outside piercing plan plant plantigrade rabid ring_piercing sea seaside shirt shorts sitting sky smoke solo stockings tail tail_markings toe_claws toes topwear tree vehicle water

2004 4_fingers 4_toes aiden_harris anthro black_and_white bottomwear canid canine carrying_another closet_coon clothing colin_young duo feet fingers fox front_view fur happy humanoid_feet k-9 leg_grab line_art looking_down looking_up male mammal monochrome on_one_leg on_shoulders pants plantigrade procyonid raccoon shirt simple_background smile spread_arms standing tail tank_top toes topwear white_background

2006 anthro appliance artdecade black_and_white bottomwear bowl building canid canine canis child clothing comic container cutlery dialogue duo english_text female furniture glass good_parenting house inside kitchen_appliance kitchen_utensils male mammal monochrome mother_(lore) multiple_scenes outside pants parent_(lore) plant sink smile smoke snow son_(lore) spoon table tail text toaster tools tree window wolf wood young young_anthro young_male

2006 anthro artdecade black_and_white bottomwear bowl canid canine canis car child clothing comic container dialogue door door_handle doorbell doorknob duo english_text female good_parenting inside male mammal monochrome mother_(lore) multiple_scenes outside pants parent_(lore) parenting plant pole scarf simple_background snow solo_focus son_(lore) text tree vehicle white_background window wolf wood young young_anthro young_male

2006 anthro artdecade bear black_and_white bottomwear canid canine canis clothing comic dialogue english_text gloves group handwear jacket lagomorph leporid male mammal monochrome multiple_scenes outside pants rabbit scarf simple_background smile snow tail text topwear white_background wolf young young_anthro young_male

2006 all_fours anthro artdecade bear black_and_white bottomwear canid canine canis clothing comic dialogue duo english_text footwear gloves handwear jacket lagomorph leporid male mammal monochrome multiple_scenes outside pants rabbit scarf shoes simple_background sled snow text topwear white_background wolf young young_anthro young_male

2006 accident anthro artdecade bear black_and_white bottomwear canid canine canis clothing comic crash dialogue english_text footwear group jacket male mammal monochrome multiple_scenes outside pants scarf shoes simple_background sled snow text topwear unconscious white_background wolf young young_anthro young_male

2006 anthro artdecade bear black_and_white bottomwear canid canine canis clothing comic dialogue english_text footwear gloves group handwear jacket lagomorph leporid lying male mammal monochrome multiple_scenes outside pants rabbit scarf shoes simple_background sled snow tail text topwear unconscious white_background wolf worried young young_anthro young_male

anthro avian beak big_breasts bird blue_and_white bottomwear bottomwear_down breasts clitoris clothed clothing eyewear eyewear_on_head female genitals hirundinid looking_at_viewer marc_leonhardt monochrome nipples non-mammal_breasts non-mammal_nipples oscine pants pants_down partially_clothed passerine sega simple_background sketch solo sonic_riders sonic_the_hedgehog_(series) sunglasses swallow_(bird) vulva wave_the_swallow white_background

2006 anthro avian big_breasts bird black_and_white bottomwear breast_squish breasts broken_language clothed clothing dr._eggman duo english_text eye_contact facial_hair female gloves greyscale handwear hirundinid human jikylio looking_at_another male mammal monochrome mustache navel oscine pants passerine poking rape_face scientist sega simple_background sonic_riders sonic_the_hedgehog_(series) squish swallow_(bird) text topless wave_the_swallow white_background

angry anthro artist_collaboration barefoot black_and_white bottomwear clothed clothing comic desiree_lee dialogue domestic_cat english_text feet felid feline felis female fight genitals group james_m_hardiman male mammal monochrome no_underwear profanity siamese_cat sibling_(lore) simple_background sister_(lore) sisters_(lore) skirt spice_ming sugar_ming tail tail_under_skirt text twins_(lore) upskirt vulva white_background

2011 anthro awkward bella_tyler_moore black_and_white bottomwear breasts cats_n'_cameras cheetah clothed clothing comic dialogue domestic_cat english_text felid feline felis female fully_clothed furgonomic_bottomwear furgonomics group james_di_benedetto james_m_hardiman josephine_rodgers male mammal marker_(artwork) misunderstanding mixed_media monochrome pen_(artwork) shirt tail tail_button_bottoms tail_clothing tank_top text the_scream topwear traditional_media_(artwork) url

2011 abs anthro biped black_and_white bottomwear chest_tuft clothed clothing fur gun looking_at_viewer male mammal monochrome oonami pose ranged_weapon rodent sciurid shorts simple_background skeeter_(character) sketch solo standing tail topless tree_squirrel tuft weapon white_background

2006 anal anal_penetration anthro avian beak beak_fetish beak_play beak_sex beakjob bent_over bird black_and_white bottomwear bottomwear_down breasts butt canid canine clothed clothing dildo echidna erection fellatio female flame_pattern footwear fox genitals group hirundinid interspecies jikylio knuckles_the_echidna male male/female mammal miles_prower monochrome monotreme nipples oral oral_penetration oscine pants pants_down partially_clothed passerine penetration penile penis sega sex sex_toy shoes simple_background sonic_riders sonic_the_hedgehog_(series) swallow_(bird) vulva wave_the_swallow white_background

1993 anthro biped black_and_white bottomwear cheetah clothing confusion digitigrade felid feline footwear holding_clothing holding_footwear holding_object holding_shoes male mammal michele_light monochrome reebok shirt shoes shorts signature simple_background solo spots tail text text_on_clothing text_on_shirt text_on_topwear the_truth topwear traditional_media_(artwork) white_background

4_fingers anthro belly belt big_ears biped black_and_white bottomwear clothed clothing elephant elephantid fingers front_view hair hi_res male mammal monochrome muscular muscular_anthro muscular_male nails nipples pants pockets proboscidean proboscis_(anatomy) short_hair simple_background slightly_chubby smile solo standing thumbs_in_pockets topless trunk_(anatomy) tusks unknown_artist white_background

anthro antlers biped black_and_white bottomwear clothing daniruu deer english_text front_view furgonomics hat headgear headwear heart_symbol hi_res hooves horn line_art male mammal monochrome new_world_deer one_piece pants profanity reindeer shy solo spot_color text tony_tony_chopper

anal anal_penetration anthro anthro_on_anthro being_watched blue_and_white bottomwear breasts bus chimangetsu clothing comfy commercial_vehicle digital_media_(artwork) dildo duo_focus exhibitionism felid feline female female/female genitals group inside_bus kilt looking_at_another lynx mammal mattie_(chimangetsu) monochrome naked_mole-rat penetration plaid predator/prey public public_transportation rodent sex sex_toy syrae-universe toying_partner vehicle vehicle_for_hire vibrator voyeur vulva wet yamaneko_sougi

2011 accessory anthro antlers biped blue_body blue_feathers bottomwear brown_body chimera claws clothed clothing cosplay dancing digital_media_(artwork) discord_(mlp) draconequus fairiedragon999 feathered_wings feathers friendship_is_magic front_view fully_clothed hasbro hat headgear headwear horn jacket male membrane_(anatomy) membranous_wings michael_jackson michael_jackson_(character) mismatched_wings my_little_pony necktie pants parody portrait pose red_clothing red_topwear shirt simple_background smooth_criminal solo standing suit tail tail_tuft teeth three-quarter_portrait topwear tuft white_background white_bottomwear white_clothing white_headwear white_necktie white_outerwear wings

4:3 action_52 aiming anthro arbalist arrow_(weapon) belt bottomwear cheetah cheetahmen claws clothed clothing crossbow digital_drawing_(artwork) digital_media_(artwork) felid feline fur greyscale half-length_portrait hi_res holding_object holding_weapon japanese_text male mammal markings monochrome muscular muscular_anthro muscular_male nipples pecs portrait quiver_(object) ranged_weapon shirt simple_background sketch solo spots spotted_body spotted_fur tail text tokonatu topwear torn_bottomwear torn_clothing torn_topwear weapon whiskers white_background white_bottomwear white_clothing white_topwear

2008 anthro black_and_white bottomwear chain clothed clothing eulipotyphlan hedgehog male mammal monochrome oomizuao pants sega shirt side_mouth simple_background solo sonic_the_hedgehog sonic_the_hedgehog_(series) tail topwear white_background

anthro armor balls belt belt_pouch big_eyes big_head biped black_and_white bottomwear bulge canid canine clothed clothing crossdressing detailed_bulge dipstick_tail drake_fenwick ear_piercing fox front_view genital_outline genitals gloves hair handwear hatching_(art) holding_object holding_weapon loincloth male mammal markings monochrome multicolored_tail navel navel_piercing navel_ring penis_outline piercing ring_piercing scale_armor shaded short_hair simple_background skimpy solo standing tail tail_markings toony weapon white_background

barefoot blue_and_white blue_bottomwear blue_clothing blue_handwear blue_theme blue_topwear bottomwear boxers_(clothing) breasts chimangetsu cleavage clothed clothing comic convenient_censorship cross-popping_vein cunnilingus dialogue dress duo_focus electronics english_text exclamation_point feet felid feline female gloves group handwear headgear headphones headset heart_symbol hindpaw humor licking lynx male male/female mammal mattie_(chimangetsu) monochrome naked_mole-rat nipple_outline off_shoulder oral paws predator/prey procyonid raccoon rodent sex shirt sketch syrae-universe television text throwing toes tongue tongue_out topwear underwear vaginal what white_bottomwear white_clothing yamaneko_sougi

2010 anthro arched_back areola badgerben big_breasts big_penis blue_and_white bottomwear breasts bulge canid canine cheek_tuft clothed clothing dialogue english_text erection erection_under_clothing eyebrows eyelashes facial_tuft fantasizing female fluffy fluffy_tail fox fur generation_1_pokemon genitals gloves_(marking) half-closed_eyes half-erect heart_symbol huge_breasts huge_penis hyper hyper_genitalia hyper_penis imagination long_tail male mammal markings monochrome narrowed_eyes navel nidoqueen nintendo nipples open_mouth open_smile pants pecs penis pokemon pokemon_(species) shorts simple_background sketch smile snout solo speech_bubble tail text thinking_about_breasts thought_bubble tight_clothing tuft white_background yiffer_(badgerben)

2008 anthro black_and_white bottomwear canid canine clothing dingbat duo eye_contact female fox looking_at_another mammal monochrome pants piercing plantigrade procyonid raccoon romantic romantic_couple shorts simple_background sitting smile tail white_background

2011 anthro avian beak bird black_and_white bottomwear catfiddle clothed clothing dancing denim denim_bottomwear denim_clothing duo feathered_wings feathers feet felid full-length_portrait galliform happy hat headgear headwear hi_res hindpaw jeans jimmyglace lion male mammal monochrome pantherine pants paws peacock_feather peafowl phasianid portrait smile tail wings zylen_andel

2011 5_fingers :o anthro anthro_penetrating anthro_penetrating_female anthro_penetrating_human areola arm_grab arm_support arm_tuft armwear balls bared_teeth big_bad_wolf biped black_body black_claws black_clothing black_fur black_mane black_nose blush bodily_fluids bottomless bottomwear breast_grab breasts brown_hair canid canine canis cheek_tuft chest_tuft claws cloak clothed clothing crotch_tuft cum digital_media_(artwork) dominant drooling duo erection erunroe facial_tuft fairy_tales fangs female female_on_anthro female_penetrated fingerless_gloves fingers forced fur genital_fluids genitals gloves glowing glowing_eyes grey_body grey_fur grey_hair guide_lines hair hand_on_back hand_on_breast hand_on_chest handwear hood human human_on_anthro human_penetrated inner_ear_fluff interspecies larger_anthro larger_dom larger_male leaning leaning_forward legwear little_red_riding_hood little_red_riding_hood_(copyright) long_hair looking_at_another looking_at_partner looking_down male male/female male_on_human male_penetrating male_penetrating_female male_penetrating_human mammal mane mostly_nude mountain mythological_canine mythological_creature mythology night nipple_piercing nipples nude open_mouth outside penetration penile penile_penetration penis penis_in_vagina piercing ponytail portrait pubes purple_eyes rape red_clothing red_topwear saliva scar sex shoulder_tuft signature size_difference sky smaller_female smaller_human smaller_penetrated stand_and_carry_position standing standing_sex star starry_sky tail teeth three-quarter_portrait tongue tongue_out topwear torn_clothing tuft vaginal vaginal_fluids vaginal_penetration vulva watermark werecanid werecanine werecreature werewolf white_bottomwear white_clothing wolf wraps

anthro biped black_and_white bottomwear clothed clothing collared_shirt computer derp_eyes dragon electronics english_text fully_clothed hair laptop line_art male monochrome mythological_creature mythological_scalie mythology pants polo_shirt scalie shirt short_hair sitting solo tail text toony topwear unknown_artist

anthro barefoot biceps big_breasts biped black_and_white bottomwear breasts canid canine canis cigarette clothing dog_tags feet female fingerless_gloves gideon gloves graphite_(artwork) gun hair hand_print handgun handwear huge_breasts hyper hyper_breasts m1911 mammal monochrome muscular muscular_anthro muscular_female nipples pistol ranged_weapon short_hair shorts smoke smoking_gun solo tail torn_clothing traditional_media_(artwork) weapon wolf

2010 4_fingers abs anthro arm_tuft bad_puppy belly_tuft biped black_body black_eyebrows black_fur black_nose black_pawpads blotch bottomwear canid canine canis cheek_tuft chest_tuft clothed clothing colored domestic_dog duo eyebrows eyes_closed facial_tuft felid fingers fur grey_body grey_fur half-closed_eyes hand_on_back head_tuft hi_res humanoid_hands husky inside interspecies jockstrap kneeling leg_tuft light male male/male mammal multicolored_body multicolored_fur muscular muscular_male narrowed_eyes neck_tuft nipples nordic_sled_dog nuzzling pantherine pawpads pink_nipples quads red_background scratches_volume_4 seductive serratus shaded side_view simple_background skimpy smile snout spitz tail tiger topless traditional_media_(artwork) tuft two_tone_body two_tone_fur underwear undressing whiskers white_body white_bottomwear white_clothing white_fur

1:1 2011 accessory ball black_and_white bottomwear clothing digital_media_(artwork) equid equine feathered_wings feathers female feral friendship_is_magic glowing hair hasbro headband horn kevinsano long_hair magic mammal monochrome my_little_pony mythological_creature mythological_equine mythology princess_luna_(mlp) quadruped simple_background skirt solo sport sweater tail tennis tennis_ball tennis_racket toony topwear winged_unicorn wings

2011 5_fingers anthro big_breasts biped black_and_white bottomwear breasts cleavage clothed clothing clydesdale draft_horse equid equine evelyn_rider female fingers fist gunmouth hair hooves horse long_hair looking_at_viewer mammal midriff miniskirt monochrome muscular muscular_anthro muscular_female navel pose skirt smile solo standing tail thong torn_clothing under_boob underwear

anthro balls_outline big_bulge black_and_white bottomwear bulge clothed clothing detailed_bulge felid genital_outline gideon huge_bulge lips male mammal monochrome muscular muscular_anthro muscular_male penis_outline shorts sketch solo tail thick_bottom_lip

2011 anthro big_breasts black_and_white bottomwear breasts camel_toe cleavage clothed clothed_female clothed_male clothing domestic_cat duo english_text exclamation_point eye_contact eyewear felid feline felis female glasses grin interrobang looking_at_another male mammal marker_(artwork) max_blackrabbit monochrome open_mouth panties pants panty_shot pen_(artwork) question_mark shirt signature simple_background skirt smile surprised tail tail_under_dress text topwear traditional_media_(artwork) underwear upskirt white_background

absolute_territory admiring anthro armwear biped bite biting_lip biting_own_lip black_bottomwear black_clothing blush bottomwear clothed clothing digital_drawing_(artwork) digital_media_(artwork) duo earth_pony equid equine eyewear female female/female fishnet_clothing fishnet_footwear fishnet_legwear footwear friendship_is_magic full-length_portrait garter_belt garter_straps glasses goggles grey_armwear grey_background grey_body grey_bottomwear grey_clothing grey_eyewear grey_footwear grey_hair grey_handwear grey_legwear grey_skin greyscale hair handwear hasbro horn horse humanoid_pointy_ears jrvanesbroek legwear lips mammal mane monochrome my_little_pony mythological_creature mythological_equine mythology octavia_(mlp) open_mouth panties pattern_armwear pattern_bottomwear pattern_clothing pattern_footwear pattern_handwear pattern_legwear pince-nez pointy_ears pony portrait rear_view self_bite shirt_collar shirt_cuffs simple_background sketch skirt socks spot_color standing striped_armwear striped_bottomwear striped_clothing striped_footwear striped_handwear striped_legwear stripes sunglasses tail teeth thigh_highs thigh_socks topless translucent translucent_bottomwear translucent_clothing underwear unicorn vinyl_scratch_(mlp) white_armwear white_bottomwear white_clothing white_footwear white_legwear

1:1 2009 4_toes accessory anisodactyl anthro avian avian_feet beak big_breasts biped blue_clothing blue_panties blue_underwear blush blush_lines bottomwear breasts butt chest_tuft claws clothed clothing feathered_wings feathers feet female hair kemonon looking_back necktie non-mammal_breasts open_beak open_mouth orange_eyes orange_hair panties pink_body pink_feathers raised_bottomwear raised_clothing raised_skirt red_eyes red_hair short_hair simple_background skirt solo standing talons tan_feet toe_claws toes tuft underwear white_bottomwear white_clothing white_necktie white_skirt winged_arms wings yellow_background

2011 anthro avian bigbangchiller bikini bird black_and_white bottomwear canid canine canis clothed clothing dutch_angle female full-length_portrait graphite_(artwork) gull hi_res jewelry lari larid looking_at_viewer mammal mia_ishata monochrome portrait sea ship skimpy skirt solo sunset swimwear tail tight_clothing traditional_media_(artwork) two-piece_swimsuit vehicle water watercraft wolf

2008 anthro black_and_white bottomwear breast_play breast_suck breasts canid canine canis chest_tuft cirrel claws clothed clothing clothing_lift digital_drawing_(artwork) digital_media_(artwork) duo english_text eyes_closed eyewear female female/female fur glasses golden_jackal hair hand_behind_head hand_on_breast inner_ear_fluff jackal long_hair mammal monochrome nohni_wabanda open_clothing open_shirt open_topwear raven_hunt shirt side_boob simple_background skirt skirt_lift standing sucking tail teacher text topless topwear tuft white_background wolf

anthro black_and_white bottomwear breasts canid canine cleavage clothed clothing corset duo eyewear female goggles jesarya lingerie male mammal monochrome romantic romantic_couple simple_background skirt tail tattoo tattooz topwear unknown_artist

anthro biped black_and_white bottomwear breasts cargo_pants clothed clothing conditional_dnp feet female hindpaw jenny_(slither) komodo_dragon lizard monitor_lizard monochrome nipple_outline non-mammal_breasts pants paws reptile scalie sefeiren shirt simple_background sketch solo standing tail topwear white_background

anthro black_and_white bottomwear breasts chair clothed clothing conditional_dnp feet female furniture fys glowing hindpaw hyena kindle_(object) mammal monochrome pants paws recliner sefeiren shirt simple_background sketch solo spots spotted_hyena tail tentacles topwear white_background