Because sbot makes use of public/private key cryptography, there's no logging in and logging out of sbot. You're 'always in' if your machine is on. More than that, because of the way sbot is built, you can respond to posts that are locally cached and if you're not connected to the internet, those responses will be 'saved' in sbot database and gossiped the next time you sync with the network.
That means you might want to use a password to lock your machine(s) when you're away. There's a thread on keeping your machine safe on sbot. To find it, go into the search bar and type ?pass to see a few conversations about the different ways people are protecting their keys.