Originally Posted by Bill O'Rights

Now that I'm done reminiscing, let's get to the topic at hand. As has been stated, the primary purpose behind "tucking" the undershirt is/was to keep it from riding up, and bunching over the beltline. This was an old military trick from way back. (Before my time even.) When I was in the service, we even had "shirt garters". These were little "Y" shaped pieces of elastic, with fasteners on all 3 ends. The idea was to attach the top of the "Y" to your shirt tail, run the bottom down the side of your leg, and hook the bottom to the top of your socks. This not only kept your shirt tucked in, it kept your socks from falling down. It's what helped to keep the Security Police looking crisp, and sharp, after a 12 hour shift.