It makes men sterile by keeping sperm out of the fluid that spurts from the penis during sex. Sperm are the reproductive cells in men. Pregnancy can happen if a sperm joins with a woman's egg. Sperm are produced in the testicles. They pass through tubes, the vas deferens, to other glands and mix with seminal fluids to form semen.
Vasectomy blocks the vas deferens and keeps sperm out of the seminal fluid.
The sperm are absorbed by the body instead of being ejaculated. Vasectomy does not affect masculinity. And it will not affect your ability to get hard and stay hard. The same is true for your sex organs, sexuality, and sexual pleasure. No glands or organs are removed or altered.