(The following has been translated using Google Translate.)
My name is Rafael (Nadal) and I play tennis. In fact I play tennis rather well but I need your help with a personal matter. If you have ever seen me play you might have noticed that I have a problem with my underpants. I think that is what they are called in your language. The problem is this. At the start of every point and I mean every point I find it necessary to pull my pants from out of my crack. I buy only the best Calvin Kleins but no matter what size I buy they always ride up and this is very uncomfortable. So uncomfortable that it has started to cause a problem with my game and I fear losing my number one status. Please help.
I must say that I sympathise with your problem. There’s nothing worse or more distracting than a pair of shreddies that keep riding up your crack. This used to happen to me and I find the best solution is to buy your under garments from Marks and Spencer that well known British high street store. Failing that you might consider going commando. It will improve your ranking even more.