As it turns out mpv can actually take commands remotely via `input-ipc-server`

Why would you ever want to? If you're like me you have mpv running in the background for animated backgrounds; sometimes i use music videos as my background.
With that flag above I can have another script I call from dmenu which pauses/resumes the background video

Also debian apparantly has a package for sending data to a socket on the commandline which is socat(its pretty neat)