- video: https://www.youtube.com/watch?v=f0eqo6jU9gc
- example gadget: http://www.japantrendshop.com/keitai-otohime-toilet-sound-bl...
- background and wall mounted examples: http://travel.cnn.com/tokyo/shop/sound-princess-loo-001106/
On another note, I'm surprised to see so many comments worrying about bathroom noises in what I presume is a male-dominated forum. Do these dynamics exist in men's rooms as well? In my workplace, at least, all manner of sounds accompanying bowel movements are ignored, or, judging by occasional laughs, sometimes even encouraged.
The Japanese word for sound is also pronounced "oto". So, a device which makes noise to help you be discreet...
But things that look like cognates with Japanese do exist. Notably そう ("sou") is pronounced the same as English "so" and means roughly the same thing, at least in phrases like "is that so?" and "Make it so, Number One."