The Bratislava Tractor

The Bratislava Tractor is a deviant sexual act of placing one's knees into the back of a willing participant's knees during sexual relations, mostly this is performed in mud pits or marshes. The thrusting partner must drive their partner into the deepest part of the mud via thrusting and "gear shifting" *see grar shifting*. The act then follows with the thrusting partner using only their knees, firmly braced in the backs of their half buried partner's knees, to raise the stuck partner out of the deep pit.