One day, Little Johnny saw his grandpa smoking a cigarette. So Little Johnny asked, "Grandpa, can I smoke one of your cigarettes?" His grandpa replied, "Can your penis reach your asshole?" "No", said Little Johnny. His grandpa replied, "Then you're not old enough."
The next day, Little Johnny saw his grandpa drinking beer. He asked, "Grandpa, can I drink some of your beer?" His grandpa replied, "Can your penis reach your asshole?" "No" said Little Johhny. "Then you're not old enough." his grandpa replied.
The following day, Little Johnny was in the kitchen eating some cookies. His grandpa asked, "Can I have some of your cookies?" Little Johnny replied, "Can your penis reach your asshole?" His grandpa replied, "It most certainly can!" Little Johnny told him, "Then go fuck yourself. These are my cookies!"