Swim Jock question

[inmywetbikini]

So I've seen swim jocks advertised and occasionally heard guys refer to them. But I've never worn one, and I've never noticed anyone wearing them.

So here's my question: What are swim jocks for?

A) To give a well-endowed guy extra support
B) To keep a nearly worn-out suit from being too risque
C) To wear on its own, as a sexy swimsuit
D) Fetish wear
E) All of the above

Or is it something else? Do any of you wear a swimjock under your speedo?