What is this sound I make when I am asleep?

When I am sleeping, I sometimes make a popping noise.  It wakes my wife up.  She says she does not think ti is my teeth snapping together.  But I can't figure out what it is or how to stop it.

Here is the recording:

Thanks!

Moderator comment: I have removed the link(s) as it was broken. If users want this information please use the Private Message service to request the details.

I fixed the link:

https://clyp.it/ymqlcxey