The Total Gym -- and other "glideboard" exercise machines -- tend to focus on upper-body workouts: You perch on the machine's padded glideboard, then use cables that run through pulleys to move the glideboard up and down a set of inclined rails. However, if you have an ankle strap attachment or a squat platform on your Total Gym, you can do several leg exercises that also target your butt.
Hip Extension Exercises
The best way to involve your butt muscles in a Total Gym workout is with leg exercises that incorporate hip extension: Think squats, side squats and sprinter starts. You can also do front lunges and reverse leg curls.
If you have an ankle strap for your Total Gym, you can also perform hip abduction to work your glutes. Swap one handle out for the ankle cuff and sit on the glideboard, facing the top of the rails. Place your ankle in the ankle cuff, hold the remaining handle in your other hand, and swing your leg to the side to pull the glideboard up the rails.