how the ejaculation happen and how the sperm come out?

How does ejaculation occur?

Sexual stimulation and friction provide the impulses that are delivered to the spinal cord and into the brain. Ejaculation is a reflex action controlled by the central nervous system. It is triggered when the sexual act reaches a critical level of excitement. It has two phases.

• In the first phase, the vas deferens (the tubes that store and transport sperm from the testes) contract to squeeze the sperm toward the base of the penis and the prostate gland and seminal vesicles release secretions to make semen. At this stage, the ejaculation is unstoppable.
• In the second phase, muscles at the base of penis contract every 0.8 seconds and force the semen out of the penis in up to 5 spurts.