Expansion/contraction is a very interesting tool that you can use for different things.
It is an inner event and if we follow it then we are involved with the principle. Expanding or contracting is very specific activity that we can localize anywhere we choose. It is possible to expand the body, or the organs, or the senses, or the space.
It always delivers great rewards when we are engaged with it. Experiencing our body and senses growing or shrinking fills us with the flow of vitality!