It was a blog entry from a feminist who was openly advocating a strategy of feigning sympathy with MRAs, then "ruthlessly using them for good." It was one in a three part series. The only phrases I remember from the post are 'ruthlessly use them for good' and (added later) 'this post went all explodey'

It was a perfect example of a training tool for concern trolls., probably a year or two old, and more likely was in /equality first.