A great implement for hotel rooms and other places where quiet torture is required is the humble rubber band.
I had bitch-boy with his wrists bound to a collar in a hotel room very recently. He had not cum for sometime. Sitting between his legs I touched and teased and he became so hard, (and desperate – poor boy), I then looped the rubber band, I had brought with me for the purpose, over his little erection, pulled one side of the loop as far away as it would go from the sensitive tube of flesh and then released it. An almost silent nastily stinging contact was made!
I repeated and repeated until the hardness was going. I stopped with the rubber band, teased and tickled until the full hardness returned, and then back to work with the rubber band. Sometimes I pulled the loop away from the underside, sometimes from the upper side. Thwack, thwack, thwack, thwack, thwack, again and again. There was much whimpering and a very sore little clitty by the time I had finished enjoying my sadistic game!