班门弄斧 – ban men nong fu

bān mén nòng fǔ

班门弄斧 (班門弄斧):

show off one’s meager proficiency with the axe before Lu Ban, the master carpenter

to display one’s slight skills before an expert

Examples:

你用不着班门弄斧。
nǐ yòngbuzháo Bānménnòngfǔ.
You don’t need to teach a fish to swim. or Don’t try to show off.

在你面前班门弄斧, 太不好意思了。
Zài nǐ miànqián bānménnòngfǔ, tài bù hǎoyìsi le.
I’m making a fool of myself in front of an expert like you.