Bacteria is a big cause of bad breath, so flossing your teeth and giving them a good brush will go a long way. Hopefully you’re already on top of that.
Keeping your mouth as moist as possible will wash away food particles and bacteria. We salivate less while were asleep, which allows bacteria to breed. As the Mayo Clinic notes: “If your 'morning breath' seems to last all day, you may not be drinking enough water.”
Chewing gum can be effective against sleep breath. Try one sweetened with xylitol, which inhibits mouth bacteria.
In addition to good dental hygiene, a fresh and minty lip balm gatekeeper for your kisser can work wonders. Try a lip balm with a menthol kick. Of course, you can’t just put lipstick on a pig (or bear) but if you’re keeping up with your dental hygiene, this is the best way to top it off.