This hypnosis file is a self triggerable file that makes you feel very little and small when you say "I want to be small again".  How small is up to your own imagination.  You will stay this way until either life demands you to be bigger or until you say I want to be big again.  It doesn't specify any sort of incontinence but if you get small enough it will certainly happen.  Essentially it just makes you little.

The file can be purchased here: I Want to be Small Again