Major Tom
It's a form of auto-erotic asphyxiation by using gravity.

Basically, you jack off normally; but before you nut, you squat down as low as you can to the ground and breathe short shallow breaths while still whacking it. This part is called "Getting in the shuttle."

As you nut, you jump up from that squatting position as fast as you possibly fucking can and hold your breath. This is considered "Take off."

If performed correctly, you should become VERY lightheaded and experience pure bliss due to the orgasm from your cock rocket. This is called "Being in space" due to the fact you feel like you're floating.

This is a technique that should be performed only by professionals, in a controlled environment.
Dude I tried to perform the Major Tom Technique but when I "Took off" I fucking jumped up at Mach 50 and must've ripped a fucking hole in the goddamn space-time continuum. Because the next thing I know I was laying on the ground with my dick out, covered in space juices from my trip around the sun.