Cock rings are a great way to maintain strong erections, whilst making your package look as plump and meaty as possible.
Cock rings are placed around just the shaft, or the shaft and the balls to constrain blood flow to and from the penis. This keeps a concentrated amount of blood in your sweet spot, making you look and feel thick as fuck.
These products are generally made from silicone, rubber, or jelly which ensures that they have a decent amount of stretch.
The tightness of the ring depends on the individual product, so check a few out to find what works best for you.