A vacuum erection (penis pump) device is a hollow tube with a hand-powered or battery-powered pump. The tube is placed over your penis, and then the pump is used to suck out the air inside the tube. This creates a vacuum that pulls blood into your penis.
Once you get an erection, you slip a tension ring around the base of your penis to hold in the blood and keep it firm. You then remove the vacuum device.
The erection typically lasts long enough for a couple to have sex. You remove the tension ring after intercourse. Bruising of the penis is a possible side effect, and ejaculation will be restricted by the band. Your penis might feel cold to the touch.