Lock It Now for Android
However, the phone kept running up apps in my pocket so I needed a way to lock it when I was about to pocket the device.
LockItNow is a simple app with no settings and no 'bells and whistles' (and no ads) just tap the lock icon, and the device locks.
Note: The first time it runs, it will ask for permission to lock the device. If you ever decide to Uninstall LockItNow, you will need to Deactivate it under Device Administrator in your security settings.