how come my mouth starts to stink so bad if I take a nap without brushing my teeth?

Question

If I even take a nap for like 30 minutes, my mouth feels like a septic tank.  If I sleep the whole night without brushing my teeth, it feels like my teeth are all rotted.  Why does this happen?  If I switch to a vegetarian diet, would I have the same issue?

Update:

It only stinks when I take a nap or sleep without brushing.  If I brush it doesn't stink. 

Answer 1

dry mouth................

Answer 2

Do not perform oral sex before you take a nap.  Or at least rinse your mouth out.  Semen tends to degrade quickly and can leave a rotting smell in your mouth.

Answer 3

You probably have periodontal gum disease.