I know there's a lot of requests on privacy and how it works... Leaving that aside I'd just like to get quicker access to it on mobile.
Right now, private listening is in user options screen. I go in, turn it on and then go find my playlist I want to keep private... (EG, at night time sounds of the rainforest or classical music or something)
I want to keep this private because I don't want my discover weekly and other recommendations to offer me ambient noise tracks or classical pieces. They are focused playlists to help me sleep, and are way different to my listening habits throughout the day.
So, the feature is, on the Song/Playlist/Artist/Album (dot dot dot) more controls menu, just add in a simple option which says "Listen in Private Mode".
Then I can just ad-hoc listen privately without going in and out of user profile.
Potential extra functionality...
Privacy mode persists throughout the duration of the selected playlist/album/etc and does not time out.
If I listen to a playlist in privacy mode, and then switch playlists to something else, privacy mode is disabled. I can re-enable it if I want in the ... menu, however I think a user has made a choice to switch, therefore listening preferences should be reset.
If an issue, show a notification bar very briefly onscreen (like the cannot play song blue bar that sticks to the top) that flashes up a message 'Privacy mode disabled: Enable on this (Album/Playlist/Etc) -- Easier continued privacy listening