Biker Mother of Six

A biker's greatest achievement was his brood of six kids.  He was so proud that he continually called his wife: Mother of Six, which pissed her off a lot.  But he kept referring to her as Mother of Six no matter where they went.

At end of a poker run, he shouted across the bar, "Hey, Mother of Six, you ready to go home?"

His irritated wife screamed back:  "Anytime you're ready, Father of Four!"