The first is a story of 2 siblings (bro and sis) who find a porno, have sex while watching it (I can't remember if the people in it were people they knew or not), then the brother goes and tells his friends who come back and have sex with the sister. Later, the sister shows how to have oral sex on a boy with her friends I think.
The second is two siblings are magically transported to a world where he learns to be a wizard and she becomes a nurse or a doctor. He gets involved with his sister and an elf. I think that there was something about a great battle coming but I can't recall.
Any body know what I'm talking about?