The next fanfic on my old favorites list is Buffy fanfic "Fireworks" by Angel Jade1, posted December 7th, 2002. Set in the hiatus between season five and six, Dawn tries to romance Spike by reminding him of Buffy. It doesn't go the way she plans at all.
I am actually a major Spike/Dawn shipper. It comes from having watched the show when at around Dawn's age and having an attraction to Spike. I do have difficulty using the shipping term "Spawn"; though, the alternative "Dike" is much worse. I'll just call the ship "Spike/Dawn".
"Fireworks" is a more realistic take on the ship, where it's all one-sided and gross when she tries to force it. Spike loves Buffy, not Dawn, so Dawn has to act like Buffy to have a chance with him. But she isn't Buffy, and she is unprepared for truly getting involved with Spike.
The main theme of the fanfic is the conflict of the innocence of childhood and the edginess of adulthood. Dawn finds adulthood aluring, while at the same time would prefer to take things slow. She pursues her attraction to a much older man, and leaves her comfort zone. The part where she drinks alcohol stands out the most as her flirtation with adulthood, claiming experience she lacks and gets in deeper.
Spike is actually a gross man, vampire nature aside, and not someone Dawn should really want to be involved with. When his vampire nature is factored in, it makes for a thoroughly unpleasant experience. Buffy could handle it, but Dawn can't force the situation to accept her as a Buffy substitute without general nastiness because she's not Buffy.
Spike would never get involved with her sober, and she takes advantage of his drunken state to try to get him to notice her romantically. The only way she can do this is by inadvertantly making him think she's Buffy. It makes the ultimate betrayal of her attraction when he kisses her only because he thinks she's someone else. She expects her first kiss to come with "fireworks", but she messes it up by trying to force something that wasn't there.
It's a good fanfic. It's short but meaningful. It definitely stays on my favorites list.