There are many apps out there that can help you with this like custom timed alarms which will play the song you want and turn it off after a certain amount of time - or even ones for iPhones which detect when you're dreaming!

In terms of your swallowing question - it's quite common for you to have to swallow, and it's a natural reflex of the body. Just let it happen! If you relax and don't worry about it swallowing will not hinder your progress through the WILD process or SP