belt buckling
"person from the backseat "are you belt buckling up there?" (at the sound of a belt buckle being undone)"
"when you are making out with your boyfriend/girlfriend at the drive-in movie and it leads to "something" more
""person from the backseat "are you belt buckling up there?" (at the sound of a belt buckle being undone)"" What is the definition of "belt buckling"?