put a bug in ear
put a bug in (one's) ear
To speak to one in order to impart some particular information, suggestion, hint, or warning. I've been putting a bug in his ear for months about what I wanted for my birthday, but he was totally clueless when the day came. They weren't listening to me, so I asked my boss to put a word in their ear about the importance of meeting this deadline.
put a bug in (someone's) earInformal
To impart useful information to (another) in a subtle, discreet way.