No I don't. I have noticed that people who do usually are covering up their gums because their lips go up too high.... (just an observation)
I dont normally, ... but I did last week between chipping my tooth and having it repaired a few days later. Mainly coz my BF was taking the piss out of me, ..calling me 'trailer park', ...and said I was not allowed to blow him coz letting a 'gappy hag' suck his cock would be stooping too low. Cheeky a-hole lol.