yes, there is no pocket for it, but you can just slide it in, if you know what i mean. it might move a bit if your briefs are too loose though.
What may be a better way to keep the cup in place and...
no they dont but they wear hairspray on their butt to help the leotard not ride up Some gymnasts do wear underwear. It really all depends on what is comfortable for you. I just went to gymnastics...