Summarize this article in one sentence.
Now that your arms are free, bring them up to your face and use your teeth to carefully loosen the buckle that joins the two sleeves. You only need to create some slack in the strap—after that, you can grip it through the fabric of the jacket and tug it the rest of the way out. You can also use your surroundings to your advantage if you have weak or sensitive teeth. For example, you might coax the strap out of the keeper by pushing the sleeve buckle against a table, door frame, or other nearby object. Focus on the top and bottom buckles, as these are the ones that prevent the wearer from pulling off the jacket. Undo the neck buckle by reaching back behind your head like you’re fastening a necklace. Then, bring both hands down your hips and unlatch the waist buckle like you’re tying an apron.  Your arms will still be inside the jacket at this point, which means you’ll need to do your best to grip the buckles through the fabric of the sleeves. There's no need to undo each and every buckle. However, the more buckles you can get to, the better your chances of escaping. Lean forward until the sleeves of the jacket are draped across the floor at your feet. Place a foot on the end of either sleeve, then pull your torso up and back with a jerk to slip out of the straitjacket in one smooth motion. Take a bow—you’ve done it!  Straighten up enough to take the slack out of the sleeves before you attempt to pull your torso free. To avoid falling over or losing control of the sleeves, make sure you’re standing on them with your full weight.

Summary:
Undo the sleeve buckle with your teeth. Use your free hands to open the buckles at the back of the jacket. Step on the sleeves and stand up quickly to slip out of the straitjacket.