Pants, gym shorts or spandex shorts that are so tight you can see the dimples on a dude's balls, i.e. plums.
"Fred almost dry-heaved when he saw Ted smuggling plums at the gym on Saturday."
Or, if the guy has a little Jimmy Dean and teenie peanuts -
"Ed almost fell off the stairmaster when he saw Jeremy walk in wearing tight spandex gym shorts. He was smuggling grapes."