How to activate screen lock instantly in purpose?

[Android Central Question]

I have the following use case for screen lock: I use the phone alternating in two "modes". In the first, I use it for a longer period of times with short breaks. Having the screen locked is painful here. In the other, I want to make sure that the phone is not activated by mistake, so I would like the screen to be locked.

Because of the first mode, I use a long time to lock (15 min). For the second, I'm looking for a way to lock the screen NOW.

Is there a sequence of actions or app that achieves an instant locking?

 

[B. Diddy]

Welcome to Android Central! Which phone? There should be an option for the Power button to instantly lock the screen -- look in the system settings for the Automatically Lock menu.