Tailwave

A tailwave (also known as tailwag) describes the act physically of "waving" or "wagging" one's virtual, fursuit or clipped-on tail to somebody as a form of a greeting, or when departing from their company.

Term (performance)
Alternately, a "tailwave" may add to a public performance (acting or dancing) of a fursuiter if skilled enough, either on a limited form (inertia), or full-on performance (controlled. Mechanical or physical).