The sperm prepares to enter the vagina after ejaculation (the bus is the vagina).
Stage 4: Uterotubal Junction/ Fallopian Tube
Just be cool, be cool
On its way through the cervix, the sperm joins the others towards the uterus (the roads are the pathways to the uterus) .
Stage 5: Fertilization
Wow it's really hot in here. I should take off my jacket.
The sperms enter the uterus and is pushed through the crowd with the other sperm and fights the leukocytes who try to block them from entering (the school is the uterus where the bullies wait outside).
Stage 6: Implantation
I present this certificate to...
Once inside, the sperm have to show proper swimming characteristics in order to survive and receive nourishment from the fallopian tube (inside a school, you have to behave properly in order to stay).
Once the sperm finds the egg it sheds layers of protein to be able to propel faster in order to penetrate the egg. The sperm has a bag of enzymes on its head that explodes, allowing it to penetrate the "outer-coat".
The union of the sperm and egg form a zygote that travels back down the fallopian tubes towards the uterus. The sperm determines the the sex of the baby, either an x carrying sperm that will develop into a a girl or a y carrying sperm that will develop into a boy (the diploma acts as the egg because it is the ticket to graduate like the egg allows access back to the uterus to make the baby)