Tennis Buttock

• backside, posterior, behind and its derivates (hind-quarters, hinder or the childish homophone heinie (US usage only), strictly the whole body behind the hind leg-trunk attachment), rear or rear-end, derrière (French for "behind") - all strictly positional descriptions, as the inaccurate use of rump (as in 'rump roast', after a 'hot' spanking), thighs, upper legs; analogous are:
• aft, stern and poop, naval in origin; in nautical jargon, buttocks also designates the aftermost portion of a hull above the water line and in front of the rudder, merging with the run below the water line
o apple (bottom), referring to the similar shape of the fruit, derived from the 1970s. Also likened to an upside-down heart, attributed from various, popular ads of the '70s.
o caboose, originally a ship's galley in wooden cabin on deck; also the "rear end" car of a freight train, considered a cute synonym suitable for any audience