Exposing genitals to vacuum

I wonder if your penis becomes enlargened in a vacuum. It would be like you were in a giant penis pump.

Dude.  The Darwin Awards have an incident recorded where a guy tried that...without knowing that the suction in his vacuum cleaner was created by a very sharp rotating blade about an inch into the tube.  In other words, "OH DEAR GOD, THE PAIN!! AHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!"