Jockstraps are sized by waist, so you could measure yourself, or match it up with your pants or underwear size. There are also different size lines for youth, sometimes teen, and adult - the youth and teen models have smaller cups or pouches to better support less developed guys before or during puberty.
Measure your waist and check the package, there are size ranges. There are adult, youth, and somtimes teen size ranges as well - this is based on how developed you are.
yes
Wear a jock strap.
yes
athletic supporter
Jock is the slang term for an athlete. It is a reference to a jock-strap, a men's undergarment used specifically for sports.
the one you can wear in public
put it on like a pair of underwera
Has visto mi suspensorio?
Banana Hammock
Put the cup in the jock strap and tell him to wear it like underwear...
It's a little bit uncomfortable at first to wear a jock strap, especially if you're not used to it. But it feels better to have good support when you run, and to not worry about getting hit down there.