Get ready to master the fine art and science of brinksmanship with the Fleshlight Stamina Training Unit! Similar to the classic Fleshlight SpeedBump insert, the Fleshlight STU has exaggerated textured bumps all through the length of the sleeve. The idea behind the STU (and many masturbation programmes designed to help guys 'last longer') is that you masturbate to almost the point of orgasm, and then stop, and repeat. The extreme bumps of the Fleshlight Stamina Training Unit - STU just make the challenge a little more challenging!