Unlocking a phone with okay google is useful. However, how can I lock it again using okay google. It's very handy being able to talk to my phone whilst working on the laptop but in the interests of battery power locking it again would help. Particularly if I'm using bluetooth and the phone is in my pocket. Time out is set to 15 seconds but a lot can happen in 15 seconds.
As it stands the Google Assistant which is activated by the OK Google command does not give you the functionality to lock your phone, if you ask it, the Google Assistant will tell you as much.
However there are ways round this, there is an article from MakeUseOf
which details how to do this, it does require the installation of an app and pairing it up with a custom command that you set in the Google Assistant.
My personal set up for screen locking is to lock immediately.