It's a vacum pump designed to be placed over the clitoral area and then the air inside is pumped out, creating a vacum. This enlarges the area below, so your clit becomes larger. Some people claim it makes them much more sensitive. It's temporary and the skin reverts to normal fairly quickly after removing the pump.
The same thing can be done to your nipples as well.
Ain't technology grand?
Originally Posted by Krunkman
Technology, my ass. I got a mouth that does all this and lubricates at the same time. No batteries.