Quote Originally Posted by Bruno View Post
Actually it isn't.
Going 'commando' means without underpants.

for example, there is a 'friends' episode where joey is wearing all of chandler's clothes, mentions he was going 'commando' and then begins doing stretching excercises.

I've seen this phrase mentioned once in a while.
Rich may have made this expression popular in this place, but he is not the inventor.
Sorry, I haven't watched TV for more than a year now and before that, very infrequently!

I wouldn't underestimate Rich though, if I were you.