So Karen and Claire have taken a liking to each other, and among other things, they like to meet up for coffee or have movie nights or whatever --during which they talk about, well, everything. Namely, about the awesome sex they're having (Claire/Matt and Karen/Foggy is what I'm thinking). It could either just be their conversation or have (flashback?) scenes of the actual acts throughout the fic. Whatever floats your boat.

And it's not necessary, but I wouldn't say I'm opposed to them getting turned on and maybe getting into Claire/Karen territory? Just sayin'.