If you want to sign out, just go into the “App Settings” tab and click “Log out”. By logging out, you won't receive notifications when you get a FlashNote, a new message or a Crush!
Please note that you will still be visible to other users.
If you want, you can go invisible for 8 hours. Your position will not be updated, no one will cross paths with you and you won’t cross paths with new people.