A sex act where the receiver is elderly and requires a Zimmer frame for mobility. Before penetration, attach some strings to some chocks,
wedge a chock under each frame
wheel for stability, hold the strings loosely in each hand, then proceed to bend the receiver over the frame and go to town.
At point of ejaculation, shout "Chocks Away!" and with one last powerful
thrust,
pull the chocks away by the strings, knocking the receiver over the Zimmer frame and onto the floor. The ejaculate will be spaffing all over the now floored (and fully satisfied) receiver.