I wear a jock all the time at the gym, a guy has got to protect the goods from harm!
Plus a jockstrap is sexy as fuck! I love to see other guys in a jockstrap, love the way the leg straps frame a guys butt. Mmmmm, mmmmm! I can spend hours at the YMCA just browsing the rows of lockers. But I've notice that jockstraps have fallen out of fashion or something. I see less and less of them in the locker rooms these days.
Usually during the summer I wear jocks instead of boxers or briefs because the ass is open and its much cooler plus it keeps everything packaged nice when I'm in shorts, no wayward dangles.
Here's my jock pic: