I have two ideas and I'd love either one or both filled. First one is she has a webcam show and for the holidays she dressed up as a sexy elf, touching herself for the viewers. One of her family members (male or female) saw it and decided after the show is done to have some real fun with her only to find out she's very willing.
Second is she has plans after the family get together to go hang out with friends, but she's bored so she decides to start drinking and starts texting who she thinks is her boyfriend some very dirty things. Only it's a family member at the party and even when she realizes it, she still keeps it going to see how much they can take. Open to males or females of any relationship to her.
You can comment here or the screened post just let me know which line and I'll toss a custom up.