Rule 34 Dev - 2015 abstract_background all_fours anatomically_correct anatomically_correct_genitalia anatomically_correct_penis animal_genitalia anthro anus ass balls big_penis canine doggy_style duo equine erection feral from_behind fur hair hooves horse horsecock interspecies krimzen_redwing looking_back male mammal mane nude paws penis pinup pose presenting raised_tail sex simple_background spread_legs spreading wolf yaoi zoophilia|2047704632