The centaur is turned on by your growing cock. He can small it through your pants. His masive horse cock pops out its sheath and swells. Its 3 feet long and as wide a a 2 liter bottle. The tip is flaring. You walk up to his underside and grab his cock. You jack it off. The head is twitching. You take off your pants and jack yourself off as you slide his cock into your mouth. You rub it up and down. You use to hands just to pleasure it. Then you raise your ass to the flaring cock head. The centaur squirts some pre sum on your anus to lube you up. He slowly pushes the flaring cock tip into you. This is all he can do until you become their anthro donkey slave.