Booster Seat Sex Position
The secret to executing a successful Booster Seat is to attain the right momentum; although, it does help if the giver has arms powerful enough to make it happen!
This rear entry position is also ideal for anal, and is intense and physically exerting. The receiver looks as though they’re sitting in a chair, but in reality they’re held up at the waist by their partner. The receiver uses the structure under their feet for balance although they are also free to bear some of their own weight (this'll take part of the strain off the giver); however, it requires a couch or bed that's low enough to do so.
Here's a tip for the standing partner - keep your abdominal muscles engaged, your back braced and knees bent; above all else, don't overdo it or you'll be sore in the morrow!