I was wondering about the physics of volume and the penis muscle.

If you have the baseball effect, this means that the volume of the tunica will be concentrated at the top and when this happens, it creates sort of a squeeze at the bottom of the penis pushing blood either upwards or away towards the bottom. Since this happens every erection, maybe it weakens the muscle that blocks the blood in an erection? Also, maybe this would affect jelqing adversly because when jelqing, the force of blood at the top portion of the penis creates sort of a squeeze/suction effect at the base so most of the blood gets quickflowed towards the top and even when you squeeze it, the blood will be forced higher into the glans and CS thus creating a weaker jelq at the bottom.

Is there a method anyone uses that blocks blood access to the glans and CS besides just squeezing with the hand?