Leverage is a lean away from your partner’s center. This builds association in a physical, still relaxed way which increases Proprioception. Leverage is often used in playful dances as it does less to restrict perpendicular motions. This is due to leverage being self stabilizing due to Tether Principles.
We use leverage instead of other possible terms to be clear that it has no inherent association with muscle engagement.
Ideas for further Explanation:
Compression Change of Frame Lead Tether and Tether Length Leverage Based Frame