One day a Jamaican walks into a bar. The bartender says "If you can make that horse over there laugh, you can have free drinks for the night". 

So the Jamaican walks over to the horse and whispers something in his ear and the horse starts laughing.

The bartender gives the Jamaican free drinks for the night. 

The next night the same Jamaican comes back in and the bartender says "If you can make that horse cry, I'll give you free drinks again tonight." 

So the Jamaican walks over to the horse and does something then the horse starts crying.

Again the bartender has no choice but to give the Jamaican free drinks again for the night. 

So as he's pouring the first drink he asks the Jamaican what he did to make the horse laugh and what he did to make him cry. 

The Jamaican says "To make him laugh I told him I had a bigger d***k than he does, and to make him cry, I showed him."