rule 34 1boy 2020 anthro anthro only anthro penetrated black hair bovine bovine humanoid bovine penis brown background brown fur buff bull commission cum fur furry furry only green eyes horn horns looking at another male male only mammal mammal humanoid mrkatman mrkatman muscles muscular muscular male naked nude nude male penis piercing pubic hair short hair silver ring smile smiley face smiling teeth tied legs 3659877