What is a session like?
Your session will begin with a discussion of your history of injury, pain or limitation, and an assessment of your range of motion and posture, so that your therapist's work can be focused and accurate.
Your first session may be quite gentle to acquaint you with the technique.  Like peeling an onion, your therapist will begin with the outermost layer of tissue and work inward.  As you relax, they will apply long, smooth, deliberate strokes and extended stretches to your tissues.  Over time, your therapist may be able to use pressure that is quite firm to go deeper into the tissue without causing you discomfort.
You will play an active role in your sessions.  You may be asked to participate by breathing deeply as a stroke is applied.  Or you may be asked to change your position or stretch your body to help your tissues lengthen and relax.
Releasing fascia requires sensitivity and a slow approach.  You may be surprised by this or think nothing is happening.  Sometimes it is only after a session that people notice results such as greatly reduced tension and increased ease of movement.
It's possible to have some soreness afterward, especially with the first treatment.  This can be similar to what you feel after exercising, and will be temporary.  Your therapist may have advice to help you avoid residual soreness, such as drinking plenty of water.