[REQ] App topic

I have an idea for an app. I dont know if it already exists or not but an app that runs music to another phone via bluetooth. Like say you and a friend want to listen to music and you both have a device and headphones but only one device has the music. You could stream the song to the other device via bluetooth.

If this exists, please give a link. If this is posted in the wrong place, please move it.