tread carefully

To delicately handle or approach a situation in order not to upset or worsen the current circumstances, which may be precarious. Tread carefully when you ask Mom whether she's going to the party. She's been acting weird about it. We need to start treading carefully when it comes to our diplomacy—we can't afford to alienate any allies.

tread ˈcarefully, ˈwarily, etc.

be very careful about what you do or say: The government will have to tread very carefully in handling this issue. OPPOSITE: throw caution to the wind(s)