Rule 34 Dev - animal_genitalia anthro balls biped fingers fully_sheathed genitals hair hand_on_knee hand_on_leg hooves long_hair lying male mane mane_hair navel nude on_side sheath slim slim_male solo orobas_(artist) equid equine horse mammal 2010 greyscale line_art monochrome sketch traditional_media_(artwork)|13349010640