side step brother
The step brother of your step brother or step sister. (NO, not YOU or YOUR brother).
MIKE: Hey Honey, this is John, my side step brother.
HONEY: Okay, you already introduced me to your "bridge brother", who is your half brother's half brother, so I am going to guess that your side step brother is your step brother's step brother.
MIKE: You are a VERY good guesser, and YES you are correct, except that I don't have a step brother, I have a step sister.
HONEY: Oh. And when do I get to meet her?
MIKE: She is over there (Mike points). Let's go. Come on John, let's go see Sharon.
HONEY: Okay, you already introduced me to your "bridge brother", who is your half brother's half brother, so I am going to guess that your side step brother is your step brother's step brother.
MIKE: You are a VERY good guesser, and YES you are correct, except that I don't have a step brother, I have a step sister.
HONEY: Oh. And when do I get to meet her?
MIKE: She is over there (Mike points). Let's go. Come on John, let's go see Sharon.