Consensual /(?)/

Con·sen·su·al

Consensual

a.
  1. Existing, or made, by the mutual consent of two or more parties. (Law)
  2. Excited or caused by sensation, sympathy, or reflex action, and not by conscious volition; as, consensual motions. (Physiol.)

Phrases & Compounds
Consensual contract
a contract formed merely by consent, as a marriage contract.