Arijana, you make me laugh!!
No that isn’t how you say it (but I like it!)! The saying is usually not used when you say something incorrect, but when you say something you shouldn’t say – like mentioning a surprise party by accident when you shouldn’t have said anything… you would say: “Sorry, I shouldn’t have said that, I seem to have put my foot in my mouth”. Or you could “put your foot in it” if you were a bit rude to someone and they took offence.