I remember Double Occupancy because I read it, and then two weeks later, canon had *body-sharing*. But the episode was lacking in the slashy porn department -- and, oh, I'm sure there must be at least a few stories out there with Cadman masturbating in Rodney's body after a long, sweaty run, but I haven't stumbled across them yet (if you know of any, link me, 'kay?) -- and despite the kiss with Carson, not actually a lot of slashiness at all.

Very late, sorry. Fic-that-turned-out-to-indeed-be-RGR was posted mid (or possibly early) into S1, and was kinda similar to this ep.

I've read the story before but I can't quite remember it (I recognise the disneyland reference and some of the lines). that sounds like a good excuse to read it again.