Why does this question keep coming up? There are guys out there that spend the extra couple bucks to buy magnums just to make a show of it and feel good about themselves, whether they need them or not! I mean, just buy the fucking things, if they fit, good for you, if they dont, at least you can tell people you bought some. Then you are out, what, 15 bucks?
Everyone has a friend who is always talking about how big his cock is, try and sell them to him. If you dont know anyone like that, then its probably you, and if they dont fit.......