you know alphas have a big thing at the base of the cock(omegas aint have balls, betas have the basic cock and the alpha has that knot like dog), that thing goes into omegas to block the sperm from coming out and stays there like a plug, that increases the possibility of a pregnancy a lot (sorry for my bad english) ( ̄へ ̄)
The idea is that like certain canines, an alpha's penis will expand at the base to seal or "knot" them in place and preventing them from pulling out. It's supposed to increase the chance of pregnancy by keeping the semen in. I think it's also suppose to show strong arousal, put that might be a different story.
This is out of topic but anyone knows what knotting someone means? Maybe I am too dumb but I don't understand it.