When you suddenly think of something you want to say, but you don't want to interrupt someone else, you would say "Fourteen and a half <whatever>." Where the <whatever> is replaced by something that would remind you later of what it was you wanted to say. (For those of us who would forget if they don't say it right away.)
Sara wants to tell Ashley about a friend and her incident with cheddar cheese, but Ashley is in the middle of a great story of her own. Sara would pipe in "Fourteen and a half cheddar cheese" or "Fourteen and a half cheese incident." After Ashley finishes her story, either Sara or Ashley would say, "So yeah, fourteen and a half cheddar cheese?"