A ball stretcher is a male sex toy that is used to stretch and elongate the scrotum. These devices are meant to wrap around the base of the scrotum and may come with attached cock rings.
Although ball stretchers are sometimes used during cock-and-ball torture scenes, many men also find the sensation of having their testicles gently pulled away from the body very pleasurable. Regularly using ball stretchers can also permanently elongate the scrotum, which is a look that some men and women find attractive.
Your Mistress, has you tied down to the bedspread eagle. She takes a seat between your legs and strokes your scrotum, drawing your balls down. The next thing you notice is the cold shock of the steel on your stretched scrotum followed by it being completely circled by steel. She starts tightening the screws until it is held firmly in place and then she drops the device. You feel it pull your balls even further from your body as she slaps your cock.