Delightfully firm and comfortable constriction can be had with the Oxballs Unit-X Cocksling. It is made from super-stretchy material so it is quick and easy to put on and although it is stretchy, it is also durable and tough. The cock sling provides just the right amount of constriction to enhance but it is also comfortable enough to be worn for extensive sessions.
It may not be compatible with all kinds of lubes but it is compatible with most products in the market today - oil-based products are not recommended. A bit of soap and water does the trick in cleaning it.