What does buttgrind mean?

buttgrind meaning in Urban Dictionary

a sensual maneuver which required the male participant to face behind the female (or male LOL) subject, maintaining continual contact amongst the the pelvis in addition to bottom; topic one will likely then initiate some brief, violent pelvic thrusts against topic two's bottom generating an unusual sensation for the individual ROFL; or alternative 2, slow mild thursts to prolong and boost the sensuality