Might be a repost but here is a Joke my dad told me a few years back.

A young boy named Johnny is visiting his grandparents, he and his grandfather are watching a movie while Johnny sits on his lap.

Johnnys grandfather then proceeds to light a cigarette and Johnny asks if he can try. So his grandfather asks:

“Does your dick touch your asshole?”

“No”

“Then you are not old enough to try”

Later the same scenario happens but it is with a beer instead, when Johnny asks if he can try the same question was asked:

“Does your dick touch your asshole?”

“No”

“Then you are not old enough to try”

A few hours later Johnny comes back in with a couple cookies that his grandmother made for him, his grandfather asks if he can have one and Johnny replies with:

“Does your dick touch your asshole?”

The grandfather smiles and proudly answers:

“Yes, in fact it does”

“Good, then you can go fuck yourself because grandma made these for me!”