Sex Flush is one of the ways human body responds to sexual activity. For some men and women, when they reach orgasm, their body skin suddenly becomes pinkish, red and blotchy or some will profusely sweat. You need not come to a conclusion that they are sick or going to die due to short of breath. There is nothing to worry about, they are just going through what is called as Sex Flush.
This drastic change in skin colour and appearance or profuse sweating is called as vaso congestion, which happens due to an increased blood pressure and swelling of tissues due to increased flow of blood. Vaco congestion can occur during erections, nipple hardening, clitoral swelling and orgasm.