Buffy and Spike are both rockstars on a tour bus

I can't remember if they are in a band together or if they are in separate bands that are touring together. They have a highly publicized animosity towards each other. They end up having a secret tryst on the tour bus. I'm pretty sure it wasn't a long story, any help would be super appreciated!

War, Music and Rampant Sex by Nicky
Buffy, the lead singer of a rock band has spent the last few months traveling in a tour bus with her band, Xander, Angel, Oz, and the elusive Spike – the one man she doesn't get along with. But now she's feeling hot...and Spike is the only single guy on the bus.

There's also a sequel:

War, Music, and Rampant....Marriage? by Nicky
My follow-up/sequel toWar, Music and Rampant Sex for all those who wanted to see what happened after that night on the tour bus. Join Buffy and Spike on a talk-show, one year later.

That's it! Thank you!