Idiom of the day :- Tongue-in-Cheek

Usage, examples and definition of the Idiom :-

Why were you teasing Sonia about her new hairdo? She really took offense at what you said. I didn’t mean to offend her. I was simply making a tongue-in-cheek remark when i said that it was too elaborate for a girl of her young, tender age. Well, she thought you were serious. She had no idea that you were just saying that as a joke. I’m really sorry. I suppose I owe her an apology.