Cupping - a practice of Traditional Chinese Medicine (TCM)! The cups are applied, air is drawn out (creating a vacuum) and the cups hold tension over the muscle. These cups can be left in place (static/retention cupping), applied and taken off repeatedly (flash cupping) or shifted around, over lubricated skin (sliding cupping). As you can imagine, the cups pick up your skin/muscle, and then release, once taken off. This causes areas of tension to release - providing relief.
And yes, as you probably already know, these cups leave some lovely red-purple-blue bruises, but that’s all part of the fun, right? These result from ‘high tensile stress’ within the cup, causing these temporary bruises (lasting up to ~7 days or so).
I’ve personally used these a ton for neck tension (#badposture), but also for tight IT bands and chronic back pain.
According to studies, cupping can also activate the immune system by causing local inflammation and activation of the complement system, affecting the thymus and increasing lymph flow!
Reference(s): PMID: 26891653.