someone's ears are flapping(someone's) ears are flapping
informal something that you say when you think that someone is listening to your private conversation.
I can't talk now. Ears are flapping.
(someone's) ears are flapping
Someone is listening, or trying to listen, to the details of a private conversation. Let's finish this conversation in the meeting room in case people's ears are flapping nearby.
someone's ears are flapping
someone is listening intently in order to overhear something not intended for them. informal