In my shop I use a palm sander plugged into a speed control
At the right speed it can get me off in 2 minutes or less, w/o taking any clothes loose. Sometimes I'll stuff a hankercheif or rag in my pants first. And sometimes I sit in a chair w/ my pants down, lay a rag over my cock and let the sander make me come all over. And it feels so dam good it feels like I'm going to split my cock or something !! I have been using this way for many years.