I love seeing people dissecting how Eridians being ambush predators and humans being persistence hunters ends up affecting how Grace and Rocky interact and I think this goes for what they think is “cute” about the other.
Grace coos over Rocky “loafing” because to him that’s a sign of rest, trust, and vulnerability (even knowing full well that Eridians sleep on a pin cushion with everything spread out). Eridians probably take being low to the ground as a sign of aggression- like you’re trying to hide and get the better of them.
Rocky loves Grace’s bad dance moves because to Eridians, being splayed out and making yourself as big as possible is trust, rest, and vulnerability. He’s making himself well-seen. But if Rocky ever tries like- walking on two legs or shows his underside to Grace while walking Grace freaks out because on EARTH, making yourself big is the sign of aggression.
