From Longman Dictionary of Contemporary Englishhanky-pankyhank‧y-pank‧y /ˌhæŋki -ˈpæŋki/ noun [uncountable] informalSYSEX/HAVE SEX WITH sexual activity – used humorously
Examples from the Corpus
hanky-panky• Worth may have been involved in some financial hanky-panky.• It was a control on monetary hanky-panky, otherwise known as inflation.• There must be some hanky-panky, Loewenthal surmised.• Instead of a warm and fuzzy public relations tour during campaign season, she now faces endless questions about supposed hanky-panky.Origin hanky-panky (1800-1900) Probably from hocus-pocus 