Tennis Buttock

• hams, like buttocks generally as a plural, after the meat cut from the analogous part of a hog ; pressed ham refers to mooning against a window; brawn, a singular derived from the Frankish for ham or roast, is also used for both a muscular body part (but either on arms or legs) or boar meat, especially roast
• hurdies - British, origin unknown, also applied to the whole rump
• haunches
• moon was a common shape-metaphor for the butt in English since 1756, and the verb to moon meant 'to expose to (moon)light' since 1601, long before they were combined in US student slang in the verb (al expression) mooning "to flash the buttocks" in 1968.