I put my foot in my mouth.

我说错话了。

I put my foot in my mouth again.

我又说错话了。

I really put my foot in my mouth.

我真的把脚放在嘴里了。

Or they tell the person something they were not supposed to tell. The speaker might say " I really put my foot in my mouth this time."

或者说了些不该说出的话。讲话的人会说I really put my foot in my mouth this time(这次我真的说错了)。

I always put my foot in my mouth, scare her off, and end up looking like a real fool. Besides, she is way out of my league.

总是说一些尴尬的话把她们吓跑，自己就像是傻子一样，而且，我和她不是一个档次的啊，我可配不上她！