Quote Originally Posted by Bixby View Post
By default, it's turned on and off with L3 (push in on left stick) when you have a target. You can change what L3 does by going to System Configuration > Gamepad Settings (the icon that looks like a gamepad) > Button Configuration.
That's one setting I generally recommend controller users should change. A problem with having the same controller element act as both an analog movement stick and a pressable button is that it's far too easy to accidentally press it when trying to move instead, especially if that movement is quick and sudden. Lock-on is an action you definitely don't want happening accidentally when you have a sudden need to move quickly.

I died several times (and came close a few more) due to that problem before figuring out what was happening and how to stop it.