A boy askes his dad if he can have a beer. The dad says "Is your dick long enough to touch your asshole?" The boy says no. "Then you're not man enough to have a beer yet."

A few years later he sees his dad having a cigar, and he asks if he can have a cigar too. The dad says "Is your dick long enough to touch your asshole?" The boy, again, says no. "Then you're not man enough to have a cigar yet."

A few more years pass, and the son buys a lottery ticket, and wins big. His dad says "Hey son, how about sharing that money with your dad?" The son says "Gee, I don't know. is your dick long enough to touch your asshole?"
The dad says "Yes it is!"

"Then go fuck yourself."