I can relate, which is probably why this cracks me up so much. From Urban Dictionary.
"This guy knows what I'm talking about"
An expression used to diffuse responsibility for an unpopular statement made in a public setting. Typically used to imply complicity or collusion on the part of an unwilling stranger.
You: I mean, really, who hasn't made out with a rundown fat chick in a moment of drunken desperation.
You: *smile and point to a random guy in the crowd* This guy knows what I'm talking about.