Totally borrowing the design from PanoScrobbler as example:

• Show a notification about scrobbling working on the background. This ensures the user has feedback about it working.
  • Setting on app to be able to hide this feature.
• Being able to love the track, edit the listen data and cancel the scrobbling of the current track being listened at the notification.
  • Greatly simplifies loving tracks while playing, not needing additional UI within the app.

Clicking on edit, opens this popup which is drawn over current apps/window.

I would really suggest you to try that app, since it's current UI is incredible good and has tons of advanced options. Even allowing to skip such track for scrobbling, full user reports, track' info, etc. Not suggesting to just make a copy, but many elements and ideas could be considered a good "UI design" to reach.