Those are some serious Indian burns.
Indian or Chinese burn
This is a prank done by grasping the victim's forearm firmly in both hands, and then twisting the hands in opposite directions about the victim's arm, causing the tender skin to stretch, making it red and sore. Known primarily as an "Indian burn" or "Chinese burn" in the United Kingdom, Australia, and New Zealand, "buffalo skin" in India, "snake bite" or "Indian rub" in Canada, an "Indian sunburn" or "Indian rug burn" in the United States (except in some midwest states such as Wisconsin where it is known as a snakebite), "Indian burn" in France, "policeman's glove" or "hundred needles" in Hungary, "barbed wire" in the Netherlands, "needles" in Bulgaria and "Brennessel" ("stinging nettle") in Austria and the southern parts of Germany, "thousand needle stings" in the northern parts of Germany, "thousand needles" in Sweden, "Nettle" in Poland and Russia, "French Cuff" in Denmark, "kuuma makkara" in Finland, "manita de puerco" in Mexico.