The most popular sex toy owned by men is the cock ring - it's handy for solo fun and can help you have better sex by prolonging ejaculations.
A cock ring is a pretty simple device - it's a ring or strap that you slide onto your dong. It allows blood to flow into the penis but not out, reducing premature ejaculation, helping with mild erectile dysfunction and, well, helping you stay hard long enough to properly please your partner. Cock rings can cause damage if left on for more than 30 minutes - but that should be plenty of time.
The ring should be put on the penis when it is flaccid or semi-erect. Depending on the cock ring you bought, it may also loop around your balls - some men find this gives them a more intense orgasm. The ring itself can be either fixed or adjustable. Generally, the ring is placed at the base of the penis, but they can also be placed higher up your shaft. Rings with ball attachments should always go on a flaccid penis, starting with the balls - put it around one, then the other. Using lube really helps with this - always use water-based lube with a cock ring. The ring should be removed after the session - 30 minutes is the absolute max and you probably want to build up to that. Leaving a cock ring on can cause priapism, which is why ED pill ads tell you to call your doctor if you have an erection lasting more than four hours.
It is vital to get a cock ring that is the correct size. Beginners should get a stretch or adjustable ring. For fixed rings, it is very important to know the size of your erect penis. A ring that is too small can get stuck, cause pain and even put you in the ER. A ring that is too large, because well, how many guys are honest about their dongs, will be less effective. Stretchy cock rings (silicone or rubber) are recommended for first timers. Advanced users swear by metal rings for the cool against their skin and the extra weight and firmness. Most cock rings, however, are made of silicone, because it feels good and is very easy to clean.
Cock rings have been around forever - we've found them at ancient Roman and Greek sites and they were documented during China's Jin Dynasty - so you're in great company if you choose to use one. Just be careful - and pick the right one for you.