Ah, I believe you misremember! Or perhaps I do. In any case, the first slash I believe I ever read was Harry/Snape. The plot in a handbasket was that Snape for some reason was required to go to the Dursley's over the summer to guard Harry, and in the process they fell in wuv. Looking back, it wasn't really that bad plot-wise; the author had side-plots and everything.

I think the worst part for me was when Snape transfigured the Dursleys into cockroaches and put them in a glass jar so they could watch him and Harry smex it up in Vernon and Petunia's room.

...

Yeah, it's a pretty vivid memory.