girl thing/guy thing

guy thing

n. something that appeals to men; something that men do. We just do it. We don’t know why. It’s a guy thing.
See also: guy, thing
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions

girl thing/guy thing

Something particularly appropriate for or appealing to a girl or guy (woman/man). Girl Thing was the name of an all female British band popular in the late 1900s. This slangy sexist expression dates from the same period. For example, “The Monday night football games are definitely a guy thing,” or “Shopping for jewelry—that’s a girl thing.”
See also: girl, guy, thing
The Dictionary of Clichés by Christine Ammer
See also:
  • a guy thing
  • guy thing
  • remember, remember, the fifth of November
  • Mr Nice Guy
  • Mr. Nice Guy
  • penny for the guy
  • big guy
  • a drag
  • a line on (someone or something)
  • a mean something