You are going to learn a lot of different things when you begin studying to become a massage therapist.
One important part of those studies will be learning about the use of external agents in massage therapy.
What are External Agents in Massage Therapy?
Beyond just the use of your hands and the power of touch in massage therapy, you may also learn about using things such as cold stones, heat therapy, or body oils/topicals, etc.
These examples listed above are what is often being described when you hear about using external agents in massage therapy.
Learning about how to use these things and how they can be beneficial may be a part of your massage therapy school curriculum.