An altogether more accurate term for 'bum sex', as there are
actually willies involved in it, as these authors well know. It also undergoes frequent use as a rudey exclamation of
horror, when something very
bad or irritating happens.
'
Rachel likes to have willy bum sex with boys.'
'
Kate has willy bum sex five times a
day.'
'OH WILLY BUM SEX, i forgot the biscuits :('