When you and a member of opposite sex work on the same greasy mechanical project before hooking up. Mingling the same greasy hands on one anothers body.
When you leave a hand print on her ass after a little Fort Mac Foreplay, it's not red from snacking it. It's black.
The act of giving your sister a foot massage
Mother: I saw you giving Betty Lou some West Virginia Foreplay
Me: We only went to second base afterward
When you're fooling around in a climate that's too hot for close physical contact, so you and your partner each lie on your backs and diddle each other with your hands.
"Wanna fuck around?"
"It's too hot!"
"How about a little tropical foreplay?"
"Let's do it."