戴上红领巾耍流氓
[dài shàng hóng lĭng jīn shuă liú máng]
A red scarf is an iconic symbol worn by young pioneers in China as a mark of pride and honor. The latter part '耍流氓' roughly translates to behave like hooliganism. Thus, this username implies hypocrisy - pretending to be innocent or virtuous while engaging in mischief or misconduct behind the scene.