A cultural stumbling block: Aerich was familiar with pressing a friend's hand in a show of compassion, but never a high five. It wasn't even good form to knock on a door in the Empire, though to be fair, there were safety hazards in striking doors that might have magical wards.

He could, at the least, mirror the panda's gesture, one eyebrow raised as he watched for a sign what to do next. Maybe he should admit not knowing; perhaps his body language could say it for him, as it so often did. There was a risk of social faux pas no matter what, so he preferred to attempt meeting Po halfway.