Google may soon add Incognito Mode to the YouTube app

If you want to use the equivalent of Incognito Mode on YouTube for Android, you'll have to head to Settings / History & privacy and enable the options to pause watch and search history. It's a bit annoying to have to do that every time you want to remain incognito while using the app, so the addition of the new mode will surely make it much easier to protect user privacy.
Once you enable Incognito Mode, your activity from the session will be cleared and you'll return to the account last used when your exit the mode. Also, your subscriptions are hidden while Incognito Mode is enabled. However, some of your activity may still be visible to “your employer, school, or internet service provider.”
source: AndroidPolice