This scientist goes to an all male tribe

Over the course of his stay, he gets curious and asks tge tribe chief how the men have sex, so he tells him "Come down to the river tomorrow morning and we'll show you." The next morning the scientist goes down to the river and sees all the men gathered round a donkey and the leader tells him that since hes their guest he goes first. Not wanting to break tradition, the scientist starts kissing the donkey and then starts fucking it. Suddenly the leader says "Sir whenever ur done, we need the donkey to cross the river there's a tribe of women on the other side." XD