How the hell does a bulbus glandis work? I don't mean that it inflates during ejaculation, I need details - what tissues is it made of, what mechanism makes it inflate, why does the deflation take so long?
Is someone capable of giving me a bit of a biology lesson on it?

Pic related is my only info on its inner workings, the knot itself seems to be the a similar "sponge" to what human dicks have but larger, how is it's inflation separated from erection though? How is it triggered on ejaculation? Don't tell me there is a fucking muscle in there