Disclaimer: I don't own Spike or his Summers women. Joss does.
This may spoil things if you haven't seen till the end of BTVS and the bit in Angel which corresponds with the end. If the idea of Spike with Joyce, Buffy, or Dawn bugs you, please go away.
He always had a thing for Summers women. Women plural. Human age is the blink of an eye. Joyce thought she was old. Laughable. Joyce was honey and well-oaked wine. He didn't think he ever drank alcohol around her and he didn't think he needed it. He drank her instead. Metaphorically. He drank in the curl of her hair and the strength in her gaze. The way she held her fingers and her body just so, like a queen in hiding. She had been worn down, his Joyce had, worn down by life like it was sandpaper. Just made her gleam more. He longed for her like dark chocolate but fate had stolen her away on wings of ash before they'd even had much of a chance. Now all he had left of her was hot cocoa with blood that wasn't hers, wasn't even human. He had never wanted her blood then. Now he wondered what she would have tasted like, if it was anything like her daughter.
Ah yes, Buffy. Slayer. He'd never drunk her blood, no, but he'd been in enough bloody scrapes with her to know what it tasted like. Slayer was ambrosia, Slayer blood was always ambrosia. It had been fire and ecstasy when he'd drained that tart Nikki and it was fire and ecstasy now. Slayer was fire too, fire and steel, she shone like the warrior Michael and was twice as hard. Twice as brittle too. Drinking her was like black coffee and loving her was like thorns. He hadn't cared though, not much, he'd thrown himself upon the pinpricks like little red ruby beads.
It always had to be blood, didn't it? It had carried him through the queen without a throne and the princess with a grudge and it carried him to...Dawn.
Dawn, his little Niblet he called her. The girl so aptly named for she was truly sunshine, like bathing through the poofter's special windows. Like the world all wrapped up in a bottle all ready to drink. Like sunshine and deep pools she was, and the crispness of autumn and the abandonment of spring. He came back all soul-like and there she was. Oh, he'd noticed her before but she'd been an innocent little thing, a toy to enjoy oneself with certainly but never anything serious. Besides, she was the Slayer's sister and so when Supergirl had risen from the dead, little sister had gone back to just that. Little sister. But then he came back. And she was there. Flowing like the danger of water. With her mother it had been an axe, a moment of boiling fire that had laid her bare for the world to see. With his Niblet, it had been ice. Premeditated. Malice. Completely Serious. He hadn't doubted for an instant that she had meant her threat, had spent the next few days sleeping with one eye open. Niblet still had his lighter. Now that would be irony. The balls were bloody shuffling in his head. They didn't settle until the amulet took him to Captain Forehead and the semi-evil law firm. The demon had loved Buffy but Buffy wanted the man. So she got the man, special delivery. Problem was, man didn't want her. Funny thing really. Like falling down stairs. No wonder they'd gone platonic. Time was, Slayer said she loved him, he would have jumped on it and devoured it whole and bugger whether she meant it or not. Bu no, little soul didn't like her one bit apparently. Soul liked being out in the sun. And the soul was getting more and more dominant each day. No, human age didn't mean a paltry thing. Back in his day a girl at fifteen would've been married. a girl at seventeen would be a mother. Like Joyce was. Dawn was seventeen now. And it was past time that he make his move.