Why do people slob in there sleep?
A number of reasons; various illnesses, posture and sleeping
position, dental reasons, etc.
Those who breathe by mouth during sleep, for whatever reason,
are naturally much more prone to this (during sleep, you produce
less saliva, but also swallow less frequently, and it can build up
and trickle out the corner of the mouth if one sleeps with their
head on its side). If you snore, you likely drool a bit too, but it
may evaporate before you wake and you'll never be the wiser.