Tail high!
From WikiFur, the furry encyclopedia.
"Tail high!" is a common form of farewell amongst chakats and other species equipped with an expressive tail. It is meant to express the wish that the recipient has a pleasant day bringing that person happiness. This is derived from how when a tail is dragging on the ground, the owner of that tail is thought to be sad or depressed, but when cheery, it lifts and waves or wags. The higher it lifts, the happier the owner. It is not intended to express anything of a sexual nature.