Why are you not supposed to ejaculate for a week after a vasectomy?
The closed end of the vas needs to heal a bit to make sure it doesn’t get reopened by ejaculation. Doing so early increases the chance of the vasectomy not taking because if you pop it open now you’ve got two open ends of the tube that want to heal.
It also stings like a bitch the first couple times and that would probably be worse earlier, but can’t confirm since I waited the week lol
Think about tearing open a wound on your hand or finger.
Now think about doing the same thing inside your private area because of movement.
After it has healed you should however masturbate frequently to “flush out the system” before the final test that confirms that you’re sterile (ask your doctor, this is not actual medical advice, etc.)
Well, ejaculation uses a lot of muscles in that area. In short, it hurts and moving any area more than necessary after an operation could cause damage.