When you wake up in the morning after a rough night of drinking and realize you had anal sex the night before. But you can't remember the action or how it happened.
When you suddenly become aware that everyone you know is having anal sex, including you.
"So Mark and I were doing anal last night and––"
"Wait. You're into anal?"
"Yeah! I decided to give it another try!"
"Me too!"
"Me three!"
"Me four!"
"Whoa. It's in the analgeist."