FURVERT!

2015 anatomically_correct animal_genitalia animal_penis anus backsack balls big_penis butt digital_media_(artwork)equid equine equine_genitalia equine_penis erection feral fur genitals hair hi_res hooves horse horse_tail long_hair lying male mammal mane monochrome muscular muscular_feral muscular_male nude on_back penis puffy_anus quadruped reinkorn simple_background solo spread_legs spreading