One who conceals his boner by doubling up his underwear waistband or sometimes even wearing two pairs in order to trap the tumescent trunk. Thus allowing said deviant the ability to roam the streets without arousing suspicion or exposing his desire to tame the beast.
Photographer: 'OK I think we got the shot, girls. Let's break for 10 minutes while I reload. Hot! Hot! Hot!'
Ballerina 1: "Francesca, I swear that pervert has a sock in his pants or something. Ewww. He kept hiding it behind his tripod"
Ballerina 2: "For sure. Like, he must be a 'Waist Trap Tucker' or something. Gross."