swallow the bait
To respond to someone's actions or words in the way that they intended. Likened to a fish attempting to eat the bait on a hook. That's just what he wants you to do. Don't swallow the bait. The undercover officer changed the conversation to the recent burglary, hoping the thief would swallow the bait and confess.
swallow the ˈbait
(informal) accept an offer, etc. which has been made or prepared specially by somebody in order to get you to do something: When people read the words ‘Free Gift’ on a magazine they usually swallow the bait and buy it.A fisherman uses bait to attract fish to his hook.