GSP used to do it before every fight. At the time they were training together at Jacksons. Shad did it to be funny.
Twisting the nipples prior to an athletic endeavor has shown to stimulate capillaries in the upper torso, leading to increased blood flow and oxygen efficiency.
It's 100% true. I have been around body building my entire life, so back in the 90's that meant major steroid use between everyone I knew, myself included. before shows,(bodybuilding) jacked up guys would put ice on their nipples and that would make them hard and completely hide their puffy nipples. It's kinda crazy to see