I was carrying laundry past her enclosure when Xion started rapid fire swatting the air with one hand, kinda like a wave but like swatting a bug. Does it function like a wave but in a "PLEASE DON'T SQUISH ME WITH THAT GIANT BASKET" way?
Making a "waving" gesture is a signal of submission. This would also perfectly fit the situation: Afraid/ unsure of what is happening, usually when mistaking something for a larger animal or for the human "having puffed up".