Your body is designed for male pleasure. Your vagina exists to stimulate a penis enough that it ejaculates genetic material into you. That's literally the whole reason your vagina is there--it's supposed to cause men so much pleasure that they uncontrollably cum inside you, so you can use his DNA to make babies.
Your vagina is the product of tens of millions of years of evolution. Think about the kinds of vaginas that would have an advantage:
*vaginas that cause more male pleasure, resulting in more sperm being ejaculated faster
*vaginas that more effectively hold and direct the sperm toward the cervix and into the uterus
Aside from basic stuff like not getting in the way of a baby coming out and not getting infected, that's the whole purpose of the vagina.
I should also remind the males here that the only reason your penis exists is for the purpose of injecting sperm deep inside a woman's vagina, in order to get her pregnant. The penis's length allows us to deposit our sperm as close to her uterus as possible. If we didn't need to get our sperm deep into women, we'd be peeing out a nondescript hole like women do.
