In a controlling kind of mood? Send your sub straight to dick jail with the Master Series' Hard Stop Chastity Cage!  
This black mini Cage fully restrains and flattens out their shaft and tip. You'll lock it up tight to one of four included rings looped behind their balls before letting them say bye-bye (if you feel generous) to the cock you now own.
A key for the built-in lock is included - keep it (or make sure your key holder keeps it) in a safe place.
Hard Stop's slick ABS plastic surface and nickel-free metal accents are easy to clean with soapy water or a favorite toy care formula.
Cage - 2.1"/5.3m long, 1.7"/4.3cm wide
Ring 1 - 1.6"/4cm
Ring 2 - 1.7"/4.3cm
Ring 3 - 1.9"/4.8cm
Ring 4 - 2"/5.1cm