The first one I know is Spander. It is kinda similar to another fic but with a role reversal. Something causes Spike to go into heat and want the man sex. Particularly Xander, of course, but vamp stamina proves too much for our favorite Scooby and he eventually takes Spike to Angel. Where Spike has his wicked way (to varying degrees) with Gunn, Wes, Angel but naturally keeps going back to poor exhausted Xander.
The second one was a WIP when I read it a long time ago and I THINK that it was supposed to lead to Spander but hadn't yet. Xander's dads boss comes over for dinner and can't take his eyes off of Xan. At this point Xan is 18 so I believe that this is AU season 4. Xan overhears his dad later discussing selling him to his boss. He goes to the Scoobies for help and they blow him off with a "You're an adult he can't do that." Spike is not there at the time and I believe that he has moved into his crypt and out of the basement. Somehow Xander's parents get him declared mentally incapable or something then sign over custody to his dad's boss for a tidy profit. I believe it's Spike who makes the other Scoobs see what idiots they're being and Buffy and Willow get to the house just as Xander is being shuffled into the guys limo. They pound on the window and say something about being Xander's friends and needing to talk to him. Xander says he doesn't have any friends and the car pulls away from the girls.
Can anyone help me out here?
Wow that was fast! You guys are the best. Thanks to everyone who helped.