I had to C&P the url to see it, but I got to it.
My daughter thinks it's the episode where Michel is hiding from the annoying kids, we think Written in the Stars?
It's the red jacket. I assumed it was KaT too! LOL.
ETA - Ahh, I just went and checked the KaT screencaps. Lorelai is wearing a black jacket with a red liner and a huge red purse in that one. I knew the red stood out for some reason!
Is it seen at a place of business?
I think that's my favorite part. Luke is reacting in subdued horror to TJ's announcement that he borrowed the deodorant, and Jess just says "Allow me" and grabs it and ...chunk... into the trash it goes. Heeeee.