Reverse Flu Shot
When someone with the influenza virus inserts his penis into a healthy recipient's mouth and holds it there for at least five seconds. It is only considered a Reverse Flu Shot if the recipient gets the flu within 48 hours.
Spencer: Here, put this under your tongue.
Cindy: What is it?
Spencer: My dick. I'm giving you a reverse flu shot.
Cindy: Oh, haha. Cool.