Czar, we call that fluffing the bed sheets.
Jesika, you will never understand it, and we can't explain it. No more than womens attraction to many pairs of shoes. It is strictly a male thing. However, there is a time and place for everything. No matter what you do, he is going to continue it, so maybe discuss it with him that you don't care for it and he should be more discreet about it. Maybe tell him if he continues it openly in your presence, he will have to go to the store and buy your tampons. Strike a deal, he doesn't do it in front of you and you won't make him purchase the tampons. No boy likes buying female things, especially at that age. Of course, the b/f should go along as it appears the two boys are only encouraging each other.
Lew W (of the outgrew fluffing the sheets class)