Here is a fabulous quick tip I learned years ago from the beautiful model Cindy Crawford.
She talked about her secret for keeping lipstick off of her teeth on some shoe I was watching. I'll never forget it because it works every time!!!
Apply your lipstick. Put your index finger in your mouth. Close your lips around the finger while sliding in out. Voila! The lipstick is removed in just the right places so your teeth don't get lipstick on them.