Mmmtsss is free software for playful looping that I created in 2008. To be honest, it's an excuse to make mouth noises, and have fun and make music together.
Mmmtsss is a sound: a bass drum in your throat (mmm) and then a little hi-hat on your teeth (tsss). Do this over and over, bobbing your head, and you've got your own party. Mmmtsss mmmtsss mmmtsss mmmtsss....
Learn more and download it here.