I have a Samsung Galaxy S6. I signed into my Gmail on my friend's Samsung Galaxy S4 phone quite a bit ago. A few months and all of a sudden, yesterday I was getting notifications on my phone asking if I was trying to sign in. Because he kept getting notifications that action was required for his and my account, so I told him to leave till we could have both phones together to see what was happening. We click on his email, and if you touch the drop-down arrow, it shows mine too.
We have tried everything to remove it from his Google account so my email will not be accessible on his phone, but when we click on mine and manage accounts, it takes mine to the page where you can sync everything, and if I click all the syncing boxes, all my email come up on his phone.
How can I get my Google account off his phone? How do I take my Gmail off his phone if it doesn't sync properly and give me the option to remove my account?