We have already talked about penis rings but I haven't mentioned the ACTIS device yet. It is manufactured by VIVUS, the same company that manufactures MUSE, the alprostadil suppositories for the treatment of ED.

The ACTIS device consists of an adjustable loop that is placed around the base of the penis. It is designed to enhance erections by slowing the flow of blood away from the penis, which aids the normal erection process.

The beauty of these toys is that they only constrict the blood vessels near the surface of the penis, not the arteries that bring blood into the penis to form an erection. You should therefore put the ring before the erection and not after.

I have tried several penis rings: they're very effective but a bit uncomfortable and you shouldn't wear them for more than 30 minutes. In my case, they also delay ejaculation.

For more on this: actis.vivus.com