Quite simply a giant douche bag. More often than not, a Lacrosse player and/or some form of Jock. A male who is either obsessed with his own stomach or wants everyone to see his stomach for some unknown reason. (it most certainly doesn't have a bad itch) This male is either looking for envy among other males, to signal other belly scratchers of being part of the club, or the possibility of female attention. Look for scratching sessions anywhere from 10-15 seconds to a full 4 minutes depending on location.
Side effects of talking to belly scratchers will cause a severe loss in brain cells. Avoid as much as possible.