What happens to unejaculated sperm?

There is always sperm in the vas deferens, the tube that carries sperm from the testicles to the prostate where it is mixed with the rest of seminal fluid. During ejaculation the vas deferens undergoes rhythmic contractions that propel sperm forward. This occurs during orgasm no matter whether it is with masturbation or during intercourse. If sperm isn’t ejaculated for a long time, as would happen if a person were completely sexually inactive; or if a vasectomy were done to divide the vas deferens, they eventually die and are reabsorbed by the body, with no effect at all.