I think our best choice would be "bikini briefs" and "bikini top".
Wikipedia wrote:Bikini underwear
Types of underwear worn by both men and women are identified as bikini underwear, similar in size and revealing nature to the bottom half of a bikini bathing suit. For women, bikini underwear can refer to virtually any tight, skimpy, or revealing undergarment that provides less coverage to the midsection than traditional underwear, panties or knickers. For men, a bikini is a type of undergarment that is smaller and more revealing than men's briefs.
If you make a google picture search, you find almost as much male versions as female versions, so I think that should be fine.
For everyone who thinks that's too skimpy, I would have no problem with adding shorts of the respective materials (wich could be rp'ed as boxer shorts, boyshorts, hot pants or whatever else there is).
Pretty in pink.