How does cock pumping work in gay sex?

What is cock pumping?

Cock pumping is using a suction device on the penis.

Definition

Cock pumping is an activity that involves a device generally referred to as a penis pump or vacuum pump. This pump can be electric or manual and is generally a long cylinder that seals around the base of the penis and applies suction. While many men use penis pumps hoping to enlarge their penises, many men use these devices for masturbation because the suction caused by cock pumping can be very pleasurable and can even lead to orgasm.

About

Cock pumping can be accomplished without a partner by putting one's penis into the long cylindrical part of the pump, then using it to create a vaccuum around the penis. The pumping sensation is similar to having a cock sucked by a partner's mouth but is more consistant and can be stronger.

 Cock pumping can be done in a variety of positions and locations. Penis pumps are commercially available in magazines and on the web and are transparent, allowing the user to view his penis as the pump is used. Care should be used when cock pumping as applying too much suction can be painful or even harmful.