Actually, we're going to watch John whine because Elly wears flannel nighties.
Panel 1: As the Pattersons get ready for bed and Elly puts on the sort of flannel nightgown he associates with old ladies and spinster aunts, John asks her what she's putting on.
Panel 2: He reminds us of his biases by complaining "Come on!! Not another one of those cast-iron nightgowns?!"
Panel 3: Hearkening back to the days where Elly pretended she liked sex, he reminds her that she used to wear flimsy, slinky nightwear when they were newlyweds.
Panel 4: She looks at him and says "I didn't get cold then."
Summary: This, of course, is a subtle-as-a-knee-to-the-groin reminder that the two of them haven't gone roadside in years, To stretch the analogy, let's say that the car is up on blocks and leave it at that.
ETA: The latest banner reminds us that friendships are forever.