While this is a question asked by many newbies, it would appear from watching professional fights that even the pros haven't figured this one out. There are several good threads on this subject in the forum which you might want to search. I will just give my pitch that I don't think the cup is usually the problem, it's the cup holder. I advise against using compression shorts with the cup pouch, but rather a tight fitting jockstrap with cup pouch. From my experience compression shorts don't hold the cup close and secure to your anatomy and it can tend to shift, crushing or shearing its contents. Some fighters have lost a testicle as a result.