Tuck your head and bring your legs around. To do this during the fall, execute a three-quarter revolution - basically, a not-quite-full somersault. This is the only method that will allow a proper landing, with your back facing down.
Aim for the center of the dumpster or large box of debris.
Land flat on your back so that when your body folds, your feet and hands meet. When your body hits any surface from a significant height, the body folds into a V. This means landing on your stomach can result in a broken back.
1. Jump straight down.
2. Tuck your head and bring your legs around, executing a three-quarter somersault.
3. Aim for the center of the dumpster and land flat on your back.
If the building has fire escapes or ther protrusions, your leap will have to be far enough out so you miss them on your way down. The landing target needs to be far enough from the building for you to hit it.
The dumpster may be filled with bricks or other unfriendly materials. It is entirely possible to survive a high fall (five stories or more) into a dumpster, provided it is filled with the right type of trash ( cardboard boxes are the best) and you land correctly.