I am certainly no expert on the topic [@Dynamo Frokane], but it seems to be a form of sexual paraphilia that focuses on the other individual's intellect and intelligence from what I recall in psychology. It tends to dwell on the fantasy of someone with exceptional or remarkable knowledge, wisdom, articulation, insight and persona - the "passion" of what makes "smart" sexually attractive over other more traditional, often physical, traits. There's some focus on the aspect of being outwitted as well.

As to how the term is employed now or those who abide by it? I admittedly do not know much there.