When the penis becomes engorged with blood and hard? Where fertilization takes place?

Answer 1

Fertilization only happens when your sperm reaches the egg. If you mean when does your sperm become active? It's when you start to feel that first wave of orgasm and you know that you cannot hold back any longer. Your sperm will mix with semenal fluid and and begin loading. You will feel the need to hold it while the waves of pleasure comes over you and you will squit the load out.