Why do i need to squeeze the blood from the glans when hanging?

Im trying out the totalman compression plate. In his video and on other threads on this forum i heard you need to squeeze out the blood from the glans.
Why do I have to do that? I have read on some posts that it can cause pain if you dont, but only on higher weights. Does that mean its ok to not squeeze out the blood if you dont feel pain?

On this thread the same question was asked: Blood in the glans

I have the same experience as the OP, the slightly engorged glans help prevent the hanger from slipping off. Someone mentioned that you dont want the pressure to be on the glans, with the blood having nowhere to go. How is that bad though? We are doing things like pumping, clamping, jelqing etc, putting pressure on not just the glans but then entire penis.

Same question and same experience as your.

Thank you

With a compression hanger, the hanger acts as a clamp. As you put weight on the hanger, it forces trapped blood downward. That can cause skin darkening and petechiae, or even blood blisters.

Squeezing as much blood as possible out while tightening the clamp minimizes that. There’s still trapped blood in there; what Bib calls the "blood plug" that keeps the hanger from slipping off.