A young fellow was about to be married and was asking his is grandfather about sex. He asked how often you should have it. His grandfather told him that when you first get married, you want it all the time... and maybe do it several times a day. http://www.51education.net来自无忧英语教育幽默笑话频道

Later on, sex tapers off and you have it once a week or so. Then as you get older, you have sex maybe once a month. When you get really old, you are lucky to have it once a year... maybe on your anniversary（周年纪念）.

The young fellow then asked his grandfather, "Well how about you and Grandma now?" His grandfather replied, "Oh, we just have oral sex now." "What's oral sex?" the young fellow asked. "Well," Grandpa said, "She goes to bed in her bedroom, and I go to bed in my bedroom. And she yells, 'Fuck You', and I holler back, 'Fuck You too.