Muscle Floss helps break up intramuscular "junk" to allow for greater mobility and blood supply to an area. By squeezing the muscle in a tight wrap, then forcing it through a full range-of-motion, friction between muscle fibers helps break up fuzz, scar tissue, lactic acid and other junk in those tiny places that foam rolling and lacrosse ball techniques can't address.
When you release the band, a rush of blood washes through the muscle; this not only brings nutrients for growth and healing but also clearing out all that junk you just broke up. This is also true for injury recovery and can be used to aid the healing of strained tissue. For swollen areas, you want to promote lymphatic drainage.
To work shoulders, wrists, ankles, elbows and the little pieces within, wrap a floss band tightly around the joint (sometimes it might take two bands to cover the area) and put it through a full range-of-motion like push-ups, PVC pass-throughs, squatting, lunging, etc. For knees, wrap one band above and one band below the joint, then do some squats. This stretches all the small muscles and ligaments which can greatly improve joint pain and stiffness.