Sex in Stone Henge

[cyanide_lollies]

Okay, barely-remembered-fic request here! This is what I recall of it:

• It was a marauder's fic, and took place after they'd left school, but before Harry arrived.
• I think it actually may have been set the day/night before James and Lily's wedding.
• It was at least implied that it happened at a henge of some sort. Big, ancient rocks. Lots of magic energy. Etc.
• There may have been some sort of pagan ritual involved, or at least pagan undertones.
• I don't know if Lily was there, but it did involve the Marauders driving out there, getting wasted/stoned and spending the night outside.
• I believe that 'the end of an era/childhood/etc' was a strong theme throughout.
• At least two of the characters have sex. It was hot and stuff x)  

I was hoping this might ring a bell with someone! I remembered it out of the blue, and I'd love to read it again!

Thanks muchly!
~CL
P.S.  I'm 95% sure that this was an R/S fic...but there's a slim chance it might have been Sirius/James, and if that's the case I'm very sorry for wasting your time! =(