Jack Off Kink. There are many varieties. Here's one I've never mentioned.
Dinner was in the oven, he had some time to kill, so Collin, age 22, decided to spend it the way most young men do: A nice, long, enjoyable wank. He stripped down, put on a cock ring, and by the time he had everything ready to go, his cock was raging hard, pointing directly at the ceiling. He lubed it up generously. With his hands behind his back, he slipped the cuffs on - very loose so he could easily get out of them - slid his head through the noose he kept tied to the clothes rack of his closet, and started thrusting his cock up and down against the door jamb. As he neared orgasm, he lowered his body toward the floor and allowed his own weight to begin cutting off his breathing. The less oxygen his lungs received, the harder his cock became. The spasms wracked his body. It was amazing. Until he lost consciousness. The doorjamb, his feet, his abdomen, the floor inside and outside the closet were all splattered with his jizz; as the orgasm eased, cum oozed down his cock and dripped off his balls. His boner remained as hard as when it was jettisoning all that juice.
It's called erotic asphyxiation. Just as in hypothermia, where the organs of the body gather blood (and blood oxygen) for survival, the same thing happens during strangulation. In men, this causes (or can cause) an erection. Law & Order: Special Victims Unit did an episode where a young cop is making jokes about a victim who is found in the nude and has a boner. Stabler glares at the kid and says, "You know an erection is a side effect of strangulation, right?"
When couples do this, one partner cuts off the air supply of the other; it heightens the erection and the orgasm.
To practice it alone, as Collin did, is called Auto-erotic Asphyxiation. It's probably more common than you may realize. And it's dangerous. Collin was found dead, hanging there naked with a solid boner, cum everywhere - by his mother. It's how actor David Carradine died.
That, my dear Faithful Readers (though the minute details of the episode are made up) is a true story. It was many years ago. His mother was an acquaintance of mine. Not only was she devastated by the death of her only son (she had a young daughter at home) but she didn't understand any of it at all. She asked, I took a stab at guessing what had happened; the coroner confirmed it.
If you want to try an auto-kink when you're alone, stick to sucking your own cock:
Kink is fine. It can be fun. But, if you're into erotic asphyxiation, don't ever do it alone; always have a partner with you who can control the situation. (If you're interested, here's an article from the UK: When masturbation can be fatal.). Partner up. Besides, jacking off with a buddy is more fun!