Tweak to "auto-lock" using stock Sprint 6.5 ROM?

[cruiserandmax]

I'm tying to figure out a way to get the phone to go into lock mode whenever it goes to sleep (either by itself, or when I hit the power button). I know I can map lock to a long key press (which i have), but it's nearly impossible for me to ge in the habit of locking it manually this way every time I put the phone in my pocket. I'm hoping there is some tweak I can install without doing an entire custom ROM as I've found the stock 6.5 ROM is otherwise very stable for me, and acceptable in speed.