I've discussed the benefits of cock rings before, especially for older men. I even interviewed Dr. Elliot Justin, who has designed a cock ring specifically to measure nocturnal erections - a sign of vascular health. Dr. Justin recommends that men over 50 should 'put a ring on it' to produce firmer and longer erections by restricting the blood flow in the penis.
Over the years, I've tried, with a partner, various cock rings marketed as couples' toys, usually a small bullet vibe attached to a stretchy ring. Even Durex has something called an Intense Vibration Ring Sex Toy. I have no issues with these or other similar cock rings, and I have a few on my bedside table that I'm looking forward to testing out.