Supernatural crossover

[umbralillium.livejournal.com]

I've already checked the crossover: supernatural tag and haven't been able to find it, so maybe one of you can help. I'm looking for a really old N3/Supernatural crossover I read ages ago, before I really got into Supernatural. I remember Don and Charlie were out the woods, hiking, and run into Dean and Sam who are on a hunt. If I remember correctly, they end up pairing up, Dean/Charlie and Don/Sam, and go off searching for something and each pair ends up having sex.

I hope someone can find this for me, I've been searching for ages and haven't been able to find it.