ease dropping
When you accidentally listen in on someone's conversation, but you're still trying to act like you didn't even though you totally did.
I heard them talking about the test, but I acted like I didn't even though I failed it.
I overheard her crying about her crush, but I said "I don't know what you're talking about."
He was telling his friend about his mom, but I said "I'm not listening" even though I was.