noun
sending a follow-up LINE message before a reply
Colloquial term used among LINE users for sending another message while still waiting for a response to the previous one. Often carries a slightly impatient or eager nuance.
See also: ＬＩＮＥ
まだ返事が来ないけど、追いラインしても大丈夫かな。
I haven't gotten a reply yet, but I wonder if it's okay to send a follow-up LINE message.
追いラインは相手を急かす感じになるから、気をつけたほうがいいよ。
Sending a follow-up LINE message can make the other person feel rushed, so you should be careful.
Similar concept but for email; 追いライン is specific to LINE messages.
Compound of 追い (from 追う, 'to follow up') and LINE (the messaging app). A relatively recent coinage reflecting digital communication habits.