One WG, who was a bit sub anyway, I'd blindfolded and then got her to back up to a suction cup dildo that I'd stuck to the floor to ceiling window in a hotel room, 2nd floor, facing the car park. Pretty sure she knew where the dildo was, but happily fucked it and then continued when I removed the blindfold. Awesome, but I found it a bit scary - who knows what she was thinking!
Have also had blowjobs while driving along - very pleasant...