Genital Stimulation
The main reason that ball stretchers are used, is for the feeling they create while being worn. If you like the feeling of your scrotum being tugged on then you will likely enjoy the experience of wearing a ball stretcher. Ball stretchers tug on the sac creating pressure as well as stretching out the skin and allowing more of your nerve endings to be stimulated.
If you use a ball stretcher made of a firm material, then you will often feel a rush of blood run back into the area once the stretcher is removed which can also feel extremely good to some people.
And of course, some people just love the feeling of their balls banging around between their legs or against someone else during sex.
Aesthetic purposes
Ball stretchers create the appearance of having a lower hanging scrotum. They can temporarily stretch the skin to create ‘lower hanging fruit’ or can be worn underneath clothing for a pushed-up look. Some styles work like a push-up bra does giving you some extra oomph and a bigger mound.
BDSM play
Some styles take things a bit more seriously and are designed for humiliation, control or even discomfort. These will often be referred to as cock and ball torture and are a fairly common part of BDSM play.
This style of ball stretcher will often be made of materials with no stretch whatsoever like metal and may even feature spikes around the inside to torment the skin. Don’t be put off by these if you see them, these are not the standard design and not all stretchers are designed for this type of play.