A fluffer is a hired member of the set of a pornagraphic movie hose role is to sexually arouse the male participants prior to the takes. Presumably, the name arose, at least in part, as a mocking reference to the hair-fluffing make-up artists who kept the starlets in non-pornographic movies looking their very best in every scene.
On gay movies fluffers are typically male, while on heterosexual movies they are usually female. The occupation is frequently depicted as demeaning and contemptible, far more so than being a porn star, with an insinuation that the fluffer isn't attractive enough to perform on camera. [from wikipedia]
Wow, this adds a whole new dimension to that episode....is Seth finally admitting that he totally has a crush on Ryan and they watch a lot of gay porn together? I think so. But wait....Seth doesn't think Ryan is attractive enough to be a porn star? What a mean friend/brother/lover/hugger!