A Little Lunchtime Daddy Love

Overheard at the lunch table...
Blond Twin: "There's the funniest sign in the bathroom here. It says I'd like to live life in the fast lane, but I'm married to a speed bump."
Mom:  "What does that mean?"
Blond Twin:  "It means that someone is really slowing things down like a speed bump."
Brunette Twin: "You know Mom. Like you and Dad."
Mom:  "Really? Who is the speed bump?"
Brunette Twin:  "You of course."