Nowadays have 2 kinds:
one made of glass and the other from bamboo.
Method in which the cups are put on the body part which we want to treat, after making vacuum in the cups (when cupping after massage with aromatic oils, the vacuum is stronger, so the cups are tighter).
Usually after taking out the cups, there are signs which can be from bright color to deep purple color. The color will vanish slowly in few days.
The method is good to treat pain problems, because it makes the blood circulation better or treating cold by taking out the disease pathogen.
During cupping, there is no pain, except the vacuum feeling.