Alison Joseph Answers
You have some really great answers here! The experience varies from person to person the same way everyone sleeps differently. Depending on how dominantly you perceive information in theta state, each person will likely have differing experiences. Because I can't speak for each individual, I'll offer some thoughts around my own personal experience with past life regressions and QHHT sessions.
What I thought would happen- a loss in conscious awareness- didn't happen for me. This made me feel like it didn't work. After working with many clients and learning the modality, I find that totally somnambulistic theta states (meaning the ego goes to sleep!) is rare- and more people experience a form of "being there" while also experiencing extrasensory information.
That extrasensory information is all valuable in uncovering hidden traumas, their purpose and the way to resolve them. Some see story like pictures in the mind- like daydreaming, but unprompted. Others feel sensations like vibrations and pulsing as the energy and healing commeses. Some see flashes of lights, and some don't "see" scenes but have feelings or knowings of what is happening.
As some of the answers mention below, no experience is any more valid, real or beneficial. They're all perfect for where you are at the moment you choose to experience hypnotherapy. It helps to not have the expectation of going totally under- because the ego can get in the way of experiencing naturally what's coming to you. If the ego feels "this isnt working" it can be a less enjoyable experience. The best thing to do is just relax, allow whatever is coming into your awareness to be there and speak freely. The real decoding happens continually after the session.