Bad girl and her Grandmother

were there passing out free oranges and she was just lining up for some.
“Why, that’s awfully nice of them. I think I’ll get some for myself,” and she proceeded to the back of the line.
A policeman was going down the line asking for information from all of the prostitutes.
When he got to Grandma, he was bewildered and exclaimed, “Wow, still going at it at your age? How do you do it?”
Grandma replied,
“Oh, it’s easy, dear. I just take my dentures out, rip the skin back and suck them dry.”