Honestly, I don't stick my foot in my mouth habitually. I remember the last time it happened, and it was on the forum, so I don't think that counts as much as in a RL setting it wouldn't have happened. Before that instance -- honestly can't remember.
I own my words. Most of the time I consciously decide to own what I say before I say it so there's no way for me to be made to felt bad or embarassed by what I say. And I'm very good at backpeddling and saving potential faux pas.
The only 'foot in mouth' thing I can think of is when the spontaneity and extraversion of ENFX gets ahead of itself.
I.E. You say things things like, "She's such a nag" and then someone tells you, "That's my girlfriend" Or you say, "I hate McCain, what a tool" and your date says, "I work for him." (<--In DC this is more likely to happen then you'd think)
This is the only 'foot in mouth' scenario that I can think of for me. And I make a conscious effort to not make extreme declarations about people until I know who I'm talking to so it rarely ever happens.
And even if I say something that others would consider a 'faux pas' I often stick by my words. For instance, if I were the one to say, "Vegans are so flipping annoying!" and someone told me they were vegan, I would still think vegans are flipping annoying. I'd probably just add, "Present company excluded" or joke, "I'm sorry I didn't know that, I hope you're not annoying!"
Putting your foot in your mouth is backing yourself verbally into a social corner so to speak. Some people just constantly say inappropriate things -- things that are too crude, lewd, or just offensive. I don't consider that 'foot in mouth', that's just annoying or socially gauche.