This hypnotic experience is known to be posthypnotic suggestion. This occurs when patients or subjects are given suggestions on what to do after waking up from the trance. This is done while in a hypnotized state. The action is usually triggered by a cue also suggested while being hypnotized.
I believe the answer is: secondary prevention
Secondary prevention consist of efforts to prevent a certain diseases before it even fully developed in our body.
During this level of prevention, foreign substance or organism is already entering the victim body, but they still haven't reach the peak of their growth and start giving full effect to the body.
Answer:
Technically air. The air is the only thing known that we can, "hold" without ever having to use our hands for any known reasons. We're holding air right now. When you inhale or hold your breath, your lungs are holding air.