It's a Puck/Rachel story that's very heavy on Brittany/Rachel friendship. I think it starts after everyone finds out that Puck is the father of Quinn's baby. Brittany and Rachel's friendship is in the story just as much as the Puck/Rachel(Honestly the friendship is what I remember most about it). They rehearsing dances together and going to the mall. At one point towards the end of the story Rachel thinks she's pregnant, but isn't.
I know it's not much, but it's all I can remember. If anyone knows if anything similar happens in a story would be appreciated. I don't know why it suddenly popped into my head, but it won't go away until I find it