Rule 34 Dev - 2010 animal_genitalia anthro balls biped equid equine fingers fully_sheathed genitals greyscale hair hand_on_knee hand_on_leg hooves horse line_art long_hair lying male mammal mane mane_hair monochrome navel nude on_side orobas_(artist) sheath sketch slim slim_male solo traditional_media_(artwork)|5838044480