One day, a little boy goes over to his grandparents house and spends some quality time on the front porch with his grandfather. Grandpa is drinking a beer, and the little boy asks if he can have some. "Can your dick touch your asshole?" asks the grandpa. The little boy answers no, so the grandpa replies, "Well, then you aren't old enough to drink beer". The little boy goes back to his grandparents house about a week later and sits on the porch again with his grandpa. He asks his grandpa if he can have some of his beer. "Can your dick touch your asshole yet?" the grandpa asks. He says it still cant, so Grandpa says, "Sorry boy, but you're still not old enough to drink beer." Later, the little boy goes inside where his grandma gives him a plate of fresh cookies. The little boy goes back outside to sit on the porch again, holding his plate of cookies. The grandpa asks him if he can have one, so the little boy asks, "Can YOUR dick touch YOUR asshole, Grandpa?" "It sure can," the grandpa answers.

"Well, then go fuck yourself. These are my cookies."

That was the joke he told me the first day we met.
I laughed so hard that I fell in love.