I would not recommend it. If I did, it would have to be a long wedge-shaped base so that it can't pass through. As the motor is not that strong, I would still be careful and, last but not least, I would only use it with the hand holder on top.

Theoretically it is possible, but I don't think it's a good idea. If it is, it would have to be a very stable pad with a small angle of attack. I would also only use the walling pad with the hand holder in this situation. It's best to ask the manufacturer