It's that damn plurk meme. Sort of.
This is the Sleeping Meme. Plain and simple, your character is sleeping with another one. While sharing a bed and sleeping together with someone is very intimate, smut is not necessary.
1) Post with your character. Name and canon go in the subject line.
2) Include your preferences.
3) Tag around.
4) If you tag, pick a letter from A-H according to the diagram above. Ta-da. That's the position the characters are sleeping in.
5) That's it.