在线请扣我离线请留言
[zài xiàn qĭng kòu wŏ lí xiàn qĭng liú yán]
A playful way of asking others to contact this user. '在线' means 'online,' and '离线' means 'offline.' So it's like saying, 'Please message me if I'm online, otherwise leave a note when I'm offline.'