Not really DH's expression but FIL's and we both picked up on it. He'll call and instead of identifying himself by name, he says "Hello, this is Tommy's* dad."
The first time he did that, I answered brightly, "Hi, Tommy's dad!!"** and he cracked up so we've kept doing it the last 13 years. MIL thought it was funny to and now any cards that are sent to me or both of us are signed "Love, MIL and Tommy's Dad."
*Not DH's actual nickname.
** Inspired by a high school friend who wasn't comfortable calling my parents by first name but was asked to not address them as Mr. And Mrs. so she'd say "Hi, Pirate's Mom/Dad!"
DH has a "Stuff" expression he likes to use. If anyone says "And stuff" he says "Not the STUFF!!" in a mock horrified voice. He'll also playfully refer to any one of our children that is the subject of conversation as "The child, who's failing to mention any checks." (from the Grinch movie, when he claims "the child mentioned a check?" as an award for joining the Whobilation).
Girly, your DH reminds me of a character on "The Regular Show" who likes to say "You know who else likes ____? MY MOM!!!!!!"