Please state in which country your phrase tends to be used, what the phrase is, and what it should be.
Example:
In America, recently came across “back-petal”, instead of back-pedal. Also, still hearing “for all intensive purposes” instead of “for all intents and purposes”.
That’s called an infix, like a prefix or suffix, but, y’know, in. Some other languages use them often, but it’s just a few fun examples in English.
Also called tmesis, which includes (as was also mentioned below in this thread), abso-fucking-lutely
https://en.wikipedia.org/wiki/Tmesis?wprov=sfla1