Speedos
From wipipedia.org
Speedos are a make of swimming costume. The ones for males are very tight and show the outline of the male genitals clearly. This makes them a fetish object for some females and gay males. They come in a range of colours.
Some men are embarrassed by wearing Speedos, particularly in public. Thus they may be used as a tool of humiliation. Pink ones may be particularly embarrassing, because being flesh-coloured they are less noticeable and the wearer may at a casual glance look nude.
The term may be used generically to refer to tight swimming briefs of any make.