Anti-rotation training before actual rotational training should be the progression you follow when it comes to core training. An example of an anti-rotational exercise is the Tall Kneeling Belly Press. The key here is to resist rotation back towards the weight stack as you press the cable handle outwards. Done right, you should really feel this in the obliques. Yes, it looks like an upper body exercise and your arms may feel some of the stress, but this is really a core exercise.
The next progression here? Go to a standing position.