The first one is pretty much a horror/slasher fanfic involving the whole Glee club. I don't remember all the details, but for some reason the glee club sneaks into McKinley one night and they started getting killed once inside. It was very Scream, and the plot twist at the end of the fic was that Puckleberry did it. They were secretly dating and planned the whole thing to kill the whole glee club and end up as the survivors and get famous. Pretty much like Sidney's cousin circa Scream 4. I read this fic over at fanfiction.net at some point in my life.
The other fic involves Rachel and the Puckerman twins. She meets them somewhere and starts spending time with them/pretty much dating both of them, and then she loses her virginity to them and she has a lof of sex with them but at the end picks Noah and Aaron ends up in the friendzone. This fic was in some livejournal like 4 years ago, but I can't find it anymore.
I hope those descriptions are useful because I can't remember the titles of the fics. If you can help me find them I will love you forever.