Semen is only ever stored in the testicles. You could be celibate for over a decade and they would never inflate. It's the spine (moreover the marrow) that creates the actual semen. The spine is the superhighway of cerebral spinal fluid. After a period of 72 days the sperm cells have matured and are ready to inseminate a fertile egg. That's when they go to the testicles.
It will remain in the testicles for approximately 2 weeks. If not ejaculated then the sperm cells are reconstituted (broken down and reabsorbed into the bloodstream) for use in other organs and tissues. The whole cycle takes approximately 90 days, each cycle of retention/reabsorption strengthens/invigorates oneself. These 90 day cycles run one-after-another, in other words you could be on day 7, but 6 other cycles are running concurrently. which is why you can ejaculate multiple times.
People who live a life if celibacy have nourished bodies and if you some research there are metaphysical elements to their lives as well.
And when it gets reabsorbed it becomes cerebral-spino fluid which connects up to the brain which is why after relapsing we feel like theres a hole in our head cuz we drain it and the body will use that cerebral spino fluid to help produce sperm.
So, this isn't scientific by any means and some accounts might sound sketchy. Some people report, on long bouts if semen retention they've found their luck has improved: they make every traffic light, that job they didn't get before now they got (or one that pays more), they started doing well on stocks or bets. Some report their intuition improved: they develop a "sense" about people/situations, they guess right, the know what needs to be done. I've heard accounts about magnetism: innocence is drawn to them - kids and animals start following them or interacting more. That girl everyone wants starts flirting with you instead. So that's what I mean by metaphysical, the results are dependent on the individual and their vibration but its not Something quantifiable or scientific.