What does G2BG mean or stand for ?

When two or more users are chatting online or on an app group chat,and one of the chatters needs to leave,they politely excuse themselves by saying G2BG.

There is also a more informal and brash way of saying this  – G2G or gotto go.If you are really close with someone,u say G2G and when you are a little formal u say G2BG.