Backside Turbulence
A sexual position often leveraged when available space does not allow for a typical "North-South" thrusting motion from behind. The BT receiver moves vigorously in an "East-West" motion while the giver remains steadfastly inserted, thereby enabling intense gratification for both parties. Airline restrooms and small shower stalls lend themselves well to BT.
Wanna join the mile high club? I do but there's barely enough room for both of us in there, it'll never work. Plenty of space backside turbulence.