Got to agree with Arliss. You're being coy here. You know if you freeball in sweats, and you're even moderately well hung, people are going to notice. The same applies to boxers and sweats. It's fun sometimes - I do it, too - but don't pretend to be surprised when people stare at your dick. :smile:
If you really want to avoid being noticed, you can try boxerbriefs. They will at least keep you from flopping around, which is what draws the most attention. If you can stand to wear them (I can't) tight briefs or even a jock will hold firmly in place all but the hugest endowments. You'll still show a bulge, but it will be sort of smoothed out, immobile, and less noticeable.