OFF meet

OFF meets are typically small online get-togethers in japan with their end goal of committing a group suicide.

Notwitstanding the statement earlier, Other contries also have online group suicides. It's that Japan is one of the more popular contries to do this.
OFF meetings are typically anonymous until the people partaking meet up and commit suicide together.
An OFF meet is just one of many names one can give a group suicide meeting. Truly, It can be anything for it is simply an online internet chat room talking about killing, or offing themselves.
Many internet providers ban websites dedicated to making OFF meets. But there are still countless circulating the internet.

Informal:
Hey bro, I just found this sick OFF meet website, wanna go?

Context:
Person 1: Is everyone from the OFF meet here?
Group: Yeah
Person 1: Great. Let's jump.

Formal:
News Reporter: Just now, there are dozens of group suicides across the country happening now. Some are calling them "Suicide Pacts"; others "OFF meetings". If you or anyone you know is partaking or thinking of doing so, please call the suicide helpline in your district.