I think there's maybe one guy, possibly two in this thread that are actually talking about "crossfacing"... You other guys are talking about face cranks and meathead moves that just show a lack of technique. That's the confusion.
There are cross face moves I don't do much in rolling without telling the guy I'm going to work them, because they're dick moves... But a regular cross face, from side mount for instance, is just pushing the guy's face away from you, sliding your forearm across under their cheek/over their jaw, and securing their far shoulder, for instance. No real weight is needed, you're just turning his head and keeping it there. Now he can't look at you, and if you underhooked that far arm, knee up close to his hip or on belly... He's screwed.
Moves I DON'T often whip out are the "poor man's twister" or "The Exorcist", which are face and spine cranks where you maliciously slice your hand across the face from the back. That said, I will turn the head and then add a little pressure to get the tap. In a comp/fight, I'd use the slicing motion.
The "crossface" from inside guard is just sloppy, the other thing is a forearm choke, and the failed naked choke is just a face crank. Those are dick n00b moves you get from over intense guys that just don't want to get tapped in their first few months. These same bonehead will try to paintbrush you from inside yoru guard, or are always tryign to muscle wrist locks while standing up in your guard.
