What is 11:30?
that time of night when you just want to tap something, but you aren't too particular about who it is. Used as reason for sleeping with someone you wouldn't normally. Also note that as the time gets later, say 12:30, the girls or guys get even worse...
Sara- ew. you slept with her?
John- it was an 11:30. just needed to tap something and she was there ;)
When it's 11:30 at night and you're desperate to tap something so you sleep with someone who you would regularly dismiss. As it gets later the girls/guys get worse and worse...
"You slept with SARAH?"
"Ugh. Don't say that. She was just an 11:30."