Been there,  done that,  and  hate when it does! 

It's like some little tidbit is just itching to get out!  It's as if the subconcience has taken over the conscience part of the brain and is running the mouth!

For me,  the best way out has been to acknowledge the "faux pas"  ( is that the right term?)  and laugh about it,  so long as I haven't insulted someone!  In the case of the latter,  I have to apologize for my stupidity and ask for forgiveness. 

Just my two cents worth on it.

I do this occasionally, but as I get older, fewer and further between.

I usually blurt something out when I am "co-thinking."  My word for thinking about what the person is saying and something else at the same time.

For instance, I saw a male cousin I hadn't seen since he was a child.  He was an active child, always on the go.  Hyper active some might say...heh.  Anyway, as an adult he is very large.  In fact, he is only about 5'4" tall and has one of those hard bellies.  It literally looks like he is 9 months pregnant.

I was so shocked when I saw him.  I was co-thinking.  I was thinking about what he was saying about his job when I approached and also about how much he changed.

He hugged me and told me I looked great.  Do you know what I said?  "Bubs.  You got so fat!"

I could have yanked my tongue out and beat myself with it.  He laughed because he saw on my face a "I can't believe I just said that" look.  He grabbed his belly jiggled it and said, "I do like me some beer!"

I was mortified.  I apologized, but dang, the damage was done.  Some stuff you can't take back.  And I really didn't care that he gained weight.  Big whoop.  It was just such a shock from how I remembered him.....

This happened some years ago, but I still bite my tongue when I think about it.

All that to say...I think its human to blurt things out.  Especially in uncomfortable silences.  In fact when I was a reporter I used "uncomfortable silence" as a tool to get info.  Most people aren't comfortable with silence in a conversation unless they know the person really well.  So they just start blurting out all kinds of things.