Ballstretcher
Don't be put off by the name - the Ballstretcher is your friend! It takes advantage of the trickeries of male physiology to delay ejaculation! Pretty clever, eh? Check it out.
When a guy is gettting ready to squirt, his balls squeeze up close to his body. If they are prevented from doing so, it makes it harder for him to come. That's just how we're made, guys, we can't help it. And that's what the ballstretcher does - you can think of it as a short sleeve that extends the very stretchy skin of the scrotum, pushing the balls away from the body.
No, it doesn't hurt, unless you count the delicious hurt of wanting to come and not being able to. No, it won't permanently prevent ejaculation, but it will put it off for a while. Yes, you will have to work it a bit. Bonus. And yes, when it does go off, like a pressure cooker blowing off steam, it can be very, very intense. Double bonus!
So, don't be put off by the name! The Ballstretcher really is your friend!