Erwin has just picked up the tribute of plantain and is about to -- well, probably save it for later, he likes gross unhealthy food and wants to fry it -- when hey, s'up mama. With the obvious coolheadedness that won him a superior position, Erwin carefully lengthens the distance between himself and baby, politely. He doesn't speak Pokemon -- not fluently, and what little he knows is basically Levi-ese -- but the intent is clear. He doesn't want to upset a protective mommy.