there are two choices that are far safer and just as inexpensive. First would be Rubber O-Rings, available at any hardware store in multiple sizes. The other is Goody No Tangle Hair Ties, these do not pinch at all and can be doubled or tripled over to increase tightness and intensity. From there you can go with a real
cock ring which starts out at about $5 and can go as high as $100. Some day we will have our own, I hope and pray