The clap

So a guy and a gal meet at a bar, have a few drinks and hit it off. They decide to go back to her place and the start getting intimate. He starts fondling her downstairs with one finger and she says "use three" so he does. Then she says "use four" and then "use five" both which he does. Next she says "stick your hand in" and he does. She tells next "stick both hands in and clap". He replies "I can't", to which she replies "tight ain't it?"