Usually occurs after a long day of work or when the temperature outside reaches ball sweating level. Once the sweating of the balls begins then they become sticky and seem to attract strait to one leg. The nut sack must then be separated from the leg it is joined to only to stick back to that leg or to the other. This is usually cured by applying powder. Warning: applying too much powder can cause a dough ball to form in areas around the nuts. Very uncomfortable.
Man it was so hot today I got a bad case of magnet balls. They just didn't want to stay off my legs. So I went to the bathroom, had to wipe the sweat from around my sack, and powder them up.