Are your instructors not teaching you how to write SOAP notes? I would take your questions to them, too. They might also be able to help you connect what you feel with how you write about it.
Depending on how your client records are set up, a client's preferences regarding pressure, draping, music, etc. can be put in a permanent note that is consulted every time they return (in addition to the most recent SOAP notes), or you can keep copying it into the "P" (Plan) section of each SOAP you write. Our practice has a permament note for stuff like that so our MTs don't have to keep rewriting it, though they can certainly change it as the client's preferences change.
If you are only doing basic full-body relaxation, many of your notes will be similar, at first. However, what kind of intake are you doing? Are you asking about injury history and medical conditions? Do you note when they were in MVAs (moving vehicle accidents) and the injuries sustained in each? Do you ask whether they are on any medications or if they have been prone to headaches, bruxism (teeth grinding), etc.? Even if they "just want relaxation", the information obtained in a good, detailed intake may completely change how you go about helping them to relax. It may even inspire you to convince them to let you do focused work on a specific problem area instead, as that may provide much greater relief and relaxation than any full-body session. Note what you learn during the intake in the "S" (Subjective) section of your notes.
If you do client ROM, posture, movement, or orthopedic assessments, note what you learn in the "O" (Objective) section of your notes. This is also where you note the location and types of hypertonic tissues, tender points, trigger points, etc. If you don't know how to feel the difference between fascial adhesions and other problems, note "Possible fascial adhesion(s) at ______." If you find "crunchy", "ropey", etc. tissue feel, note it with the adjective(s) that best describe it.
"A" (Assessment) is where you note tissue changes during the session, whether the client relaxed or not, whether their symptoms changed, etc.
"P" (Plan) is primarily used for noting what you recommended to the client after the session, such as when to return, certain types of work or strategies to explore next time, whether they should see a medical professional for something, etc.