thanks, here's another one..

Peter and Jane were good friends and they always climb a tree together. Jane would wear a skirt and Peter would always let Jane climb up first. So one day when Jane told her sister about this, her sister scolded her for being stupid to have let Peter seen her undies.

The next day, Jane and Peter went to climb the tree again. Jane, as usual, wore a skirt. Peter would let Jane climb the tree first, and she did so too. She went home and tell her sister the same thing. Her sister was furious and exclaimed,

"Why ARE U SO STUPID to let him see your undies again!?!"

"No way, I didn't wear undies this time :)"