Mailbag question for turkey week program

How do you best defend slant routes? I'm in a franchise club, which only allows me to move one guy pre-snap. Lately I've been leaning toward Cover 1/ Robber in an effort to stop it. Is that the best way?

And also I need help understanding the write-up in the Prima Book on crashing the line. To make this simple. If someone comes out in normal I-formation and runs a stretch to the strong side of the line (TE side), which buttons do I press to best stop the run. My arrows on the screen should be facing my which direction as I crash the line?

is defensive commit still in the game? Was told the d-pad right after the snap would work...