spike, buffy, angel, and nina

I read this one a while back and I can't remember the name of it. Buffy teams up with Spike and Angel, who brings Nina along for some world saving mission. I think they get sucked into another reality and they're trying to find something. I do remember at one point Angel and Spike are arguing (maybe in a car) and Spike says, "What are you gonna do, Dad? Spank me?" Any recollections?

MadRog's WIP, Quid pro Quo has A/N and S/B. You can find it on the Sinister Attraction website. I don't remember them being in a car but it's a good read, I just wish it had been finished.