system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How is there always a seemingly ready and plentiful supply of sperm

If sperm cells take over two months to mature, why can someone masturbate multiple times a day consistently without running out of sperm?
gpt
Because men make several million sperm cells per day, and there are always sperm cells in various stages of production. It's not like after an ejaculation you need 2 months to make more. Today, you (if you have testicles) will finish making, let's say 30 million sperm cells. There are also 30 million more sperm cells at "99%" that will be ready tomorrow, 30 million more at  98% that will be ready the following day...etc. You also have a bunch of surplus sperm cells ,so you have multiple rounds in the chamber, so to speak.

Also, it's important to note that sperm is not the same is semen, sperm is a component of semen. Semen is almost entirely fluids from your seminal vesicles and prostate gland. An ejaculation with 50 million sperm cells is identical to one without except under a microscope. That's why men who have had vasectomies or men who are infertile can still ejaculate.

Fun extra fact: The reason testicles are external and not inside the body is because the ideal temperature for sperm production is a few degrees cooler than our core body temperature. Keeping the testicles in an external sac keeps them cooler for optimal sperm production. That's also why the scrotum can tighten and sag. If it's too cold, your scrotum will contract to bring your testicles closer to your body to keep them warm. Too warm, and it'll relax and let them hang low away from your excess body heat.