It makes me shudder with horror but if you like the idea of pair editing, Emacs has got you covered. zk-phi has released togetherly that lets you share a buffer with one or more colleagues. It works by setting up a local server to which the other users can connect with Emacs to get a view of the buffer you want to share.
As I said, it’s definitely not for me but if it’s something you would find useful you should give it a spin. It appears to still be early in its development cycle but functional. It does not appear to be in any of the ELPA repositories yet.