My balls aren't particularly huge either, but they hang, and I'm a boxers man.
Some days I'll notice especially after I spend some time edging and then eventually masturbating to orgasm, that my balls will have this particularly strange pain centered in on them. I don't know if it's because I "overwork" them or when they ease their way back down, or if I'm running around waiting tables and they do some bouncing and shaking of their own...
Anyway, whether big or small in the nuts, sounds like this thread's pressing the importance of keeping them supported adequately. (Sure, doesn't turn me to think I might get the most support in a pair of briefs, but I'm almost willing to experiment just to make sure it's a choice of underwear rather than a more serious condition.)