When using a penis pump, you would want to pump until your penis is enlarged.
Hydro series pumps will give you an excellent idea about the amount of vacuum needed, the feel of suction, and how to maintain an artificial erection.
Another This is what the Bathmate pump looks like.
Use the pump mechanism to suck the air out of the chamber.
Depending on the pump you can have your penis flaccid, hard or semi-erect.
All of a sudden, I bleed a lot after using it.