Traditionally, the manner of taking the back in jiu-jitsu involves double underhooks behind your opponent. However, this form of control lends itself to several flaws. Not only is does it not provide easy access for a choke, but it gives the opponent an escape route for either shoulder. According to Marcelo's style, back control is maintained with an overhook and underhook, known as the Seatbelt. Escaping the Double Under variation of back control is trivial; Choose a side, free your head and shoulders onto the mat, bridge to keep your hips off of the mat, and twist back to face your opponent. It is crucial to keep your hips off the mat for two reasons: 1) it will make it harder for your opponent to counter the escape by transitioning to the mount, and 2) lifting your hips up puts more weight on your shoulders, making it harder for him to pull you back into his control. If you're trying to escape from the Seatbelt, you only have one option of which side to lay on; the side of the underhook. The rest is exactly the same.