If you wish to emphasise the bulge you should go for a thin unlined stretch fabric preferably with a pouch front and in a colour that will go translucent when wet.
You'll need to consider where you wear it and who sees you in it.
Brave Person is a good place to start looking:
https://www.ebay.co.uk/itm/BRAVE-PER...AOSw88xaQK9 a