A little boy is sitting in the living room with his grandpa. Grandpa is sipping on a glass of whiskey, so the little kid asks, "Grandpa, can I have a sip of that?" Grandpa looks at him and asks, "Well that depends, can your dick touch your ass?" The little kid says, "No," so Grandpa says, "Then no you cannot."
Then a little bit later grandpa lights up a cigar. The little boy asks, "Grandpa, can I try that?" Once again Grandpa asks, "Well that depends, can your dick touch your ass? The kid responds no again and Grandpa tells him he cannot.
A little bit later Grandma takes a big pan of fresh cookies out of the oven, and gives a plate of them to the little boy. The boy walks back into the living room when Grandpa sees the cookies and asks, "Well, can Grandpa have one of those?" The little kid looks at him and asks, "Well that depends, can your dick touch your ass?" The Grandpa looks proudly and say, "Why yes it can!" The kid looks back at him and says, "Good, then go fuck yourself!"