Colin: When shall we get married?
Gwen: Not yet.
Colin: But we don’t want to wait.
Gwen: No.
Colin: Then what do you mean?
Gwen: Don’t let’s get married yet.
Colin: Oh don’t let’s have any more of that rot! (And, because his nerves are on edge, he makes it sound more explosive than he meant. Realising, he adds, mitigatingly:) I mean, it may be all right when you’re not serious, but when you are, it’s no good.
Gwen: It’s not “rot” to me.
Colin: Well—perhaps not; but we needn’t be mixed up in it.
Gwen: Leave it to somebody else.