Damn you're making me imagining some wild ass things
Ass
It depends on the author, my opinion is caesarean section but i ve read a manga on http://www.myreadingmanga.com that has FULL VIEW on how babies can be born through the ass (it was very disturbing manga i don't recommend it, it was about rape and pedophilia)
Does anyone know how male omega give birth?(〜 ̄△ ̄)〜