What causes my hands and feet to go numb after I orgasm during sex?

BLood flow. Blood flow is redirected to the areas that need the most blood flow in any given situation. During orgasm, blood flow is diverted to the heart, lungs, brain and sexual organs which could produce some transient numbness in the far extremities as blood is diverted to these areas.
Numbness after sex. . Numbness, tingling, light headed ness, and sleepiness are all commonly experienced symptoms after orgasm for both genders. Except for sleepiness the others should be transient. Given the complex interaction of cardiac, respiratory, neural, and intra abdominal pressure changes going on at the time, it is expected that these effects might be experienced. Nothing to worry about!