An 85 year old man marries an 18 year old girl.
At the wedding reception he's telling his friends how fantastic the sex is going to be.
One of his friends cations him: "You know sex is VERY stressful. If you over do it it could be fatal."
The 85 year old groom says: "I know that. I'll try to exercise a little restraint. But if she dies, she dies."