Where one assumes the characteristics of being a snake or worm, and is forced to crawl around on their belly, stomach. Used as a form of humiliation and helplessness.
Bondage uses accompany this form of sexual role playing, in which the subject is bound, so they can only use their stomach to crawl around.
Legs are bound tightly, to make them unusable for pushing the body forward.
Usually this includes bindings around both the ankles, and knees.
Wrists are usually tied behind the back, along with various elbow bondage techniques, to make the subject totally restricted in using their appendages to move.
Hoods are also used, to further enhance the feelings of helplessness.
A gag is generally used, to make speech difficult, or verbalization.
Affixing a rod, to keep the legs from flexing is also used, to further restrict use of any appendage, in movement.