Usual bodybags do not prevent you from crouching, squirming, bouncing and hopping around. This modification will render your legs almost useless without any ropes and unlike rope will not cut into your flesh. Also such a bag is a time-saver: just tie hands behind the back and zip the bag up.
Self-bondage is possible just like using any other bodybag:
- Use an ice-lock (like this one or this) inside the bag
- If you can unzip the bag with your hand bound in front of you, tie a pull-rope string to a stationary object through an ice-lock, put the cinch noose inside the bag through the collar, zip it up and cinch the noose. When the lock opens you will be able to crawl to the knife
Many thanks to Jessi for the photo.