a surfdog mom is a mother who interferes in her son's life. She will do all she can to get rid of any female whom she does not feel is good enough for her little surfdog. She will even go so far as to pay the woman off.
I had a good thing going with surdog, but then surfdog's mom offered me a lot of money to let him catch me in bed with another guy. I couldn't resist the money because it was a huge lump sum.