What's the similarity between a pork-pie and oral sex with an OAP?
You have to remove the crust first and suck out the jelly before getting to the meat.
I am very very very sorry for that one.
A man takes his friend home, only to find his wife doing naked yoga in the front room with her legs behind her head. Thinking quickly, he shouts "Show some decorum, I've got a friend with me, put your teeth in and comb your hair!"