You cannot hold in your period. Pee and period blood do not exit the body from the same place – urine exits from the urethra which has sphincters so can be controlled while period blood exits from the vagina which does not have sphincters so cannot be controlled.Also,There are two openings in the vulva — the vaginal opening and the opening to the urethra (the hole you pee out of). The urethral opening is the tiny hole that you pee out of, located just below your clitoris. The vaginal opening is right below your urethral opening.