When Christopher says that Lorelai’s reference to Fred Mertz from I Love Lucy was a weird one in that context, she replies, “Hello, pyjamas”, and gestures down at the pyjamas she is wearing.
It may not be immediately obvious to the viewer that Lorelai is wearing pyjamas with an I Love Lucy pattern on them, explaining not only that the show was on her mind, but that she truly loves the show and knows a lot about it.
The pyjamas are inspired by the famous Job Switching episode of I Love Lucy, which aired September 1952. In the episode, Lucy and Ethel get jobs at a candy factory while their husbands have to do the housework for a week. There is a classic scene where Lucy and Ethel try to wrap chocolates as they come off the conveyer belt, with disastrous results. It is this which Lorelai’s pyjamas commemorate.
You can buy a pair of these pyjamas from The Lucy Store, and elsewhere, for about $50.