assuming you're already lean, bicycle crunches.
i fucking love my obliques lol. had to train them hard to avoid getting rekt by body shots
Quote (noob_whacker @ May 23 2015 07:30pm)
http://www.bodybuilding.com/exercises/exerciseImages/sequences/208/Male/m/208_2.jpg
this is a really good one too, to do high volume light weight