In days gone by swimming trunks were bulky items in thick material with high waists seemingly designed to obscure all hint of sexual interest.
That could be circumvented of course for photographic purposes but not in public.
Now-a-days trunks are much more interesting with skimpy cuts and flimsy fabric intended to promote speedy performance in the pool. By a happy coincidence these same requirements provide 'man fans' with tantalising glimpses of bulges (3) ...........
...........and shaved stomachs (4).
It takes little effort to conjure up 'mitchmen' style fantasies of these young athletes helping each other with their intimate preparations for competition.
Or perhaps their older coaches do the job for them.