Dribbling!

Is it just me, or am I the only one who turns into a dribbling mess when I fall asleep? And sometimes at other times too! For example, I leaned forward yesterday (from a sitting on the settee sort of position) to pick something up off the floor and dribbled a small puddle of dribble onto the floor! What's that all about?? And I often have little damp patches on my pillow from dribbling in my sleep! Whatever next??