The last thing you said, and the reply.

[Abide with me.]

Write whatever you last said, whether it makes any sense or not, and the reply, even if it's " Why not? And the reply can be "You know why not!" And leave us guessing what the conversation was about.
Here's my last conversation.

Me.."she's trapped in the conservatory" reply " How can she be, she's asleep under that cushion"!