Mars逢场做戏
[mars féng chăng zuò xì]
This username suggests someone who views their online interactions or even their real-life relationships in a playful, non-serious way. 'Mars' indicates the person may have a strong, independent or even slightly distant character like the god of war or the planet Mars. '逢场作戏' is an idiom that translates to acting on the spur of the moment or engaging in insincere behavior.