Wiktionary
tread lightly
vb. (context idiomatic English) To proceed carefully; especially, to seek to avoid causing offense.
Usage examples of "tread lightly".
You can tread lightly, so you walk right onto the bridge itself, and they won't hear you.
Though they tried to tread lightly, their footfalls on the oak floor echoed hollowly through the empty church.
We are much more inclined to tread lightly if we have your cooperation.
The adjutant's belief that they had to tread lightly was supported by the way the authorities sequestered the Swift in a closed dock and ordered the crew to stay buttoned up until further instructions.
Ishido knew that while his mother was in Toranaga's power he had to tread lightly.