There is a suction created with the cups that creates a gentle “vacuum” type sensation to the top layer of skin or fascia. The suction can be more aggressive if necessary. This is used to break up tension, adhesions, and soften fascia so to relieve issues in the muscles. It is common to see evidence of the work as it brings stagnant blood and lymph to the surface creating the appearance of a bruise. These marks will usually resolve themselves within a couple days.