rule 34 2013 abdominal bulge abs animal genitalia anthro anthro on anthro biceps big dom small sub big penis blue eyes bodily fluids breasts brown hair cum cum inside duo equid equine erection felid feline female female penetrated from behind position fur furry genital fluids genitals hair interspecies larger male male male penetrating male penetrating female mammal muscular muscular anthro muscular male nude open mouth pantherine pecs penetration penis predatorprey saruuk sex sheath size difference smaller female smaller penetrated straight stripes tongue vein vivarium yellow eyes zebra zoological gardens 1347637