Cupping is a very old technique that is used by acupuncturists to release stagnation and heat from the body. A glass cup is suctioned to the skin and either left in place or moved around to help release superficial and deep adhesions.
I find cupping especially effective for increasing flexibility and breaking up scar tissue from injuries and chronic tension patterns. Often cupping leaves marks like bruising that can take a week to disappear. Before I use this technique I explain this to my clients so they can decide if they are ok with the markings.