A few months after buying our Model X, the driver’s side window started squeaking loudly every time we rolled it down. The video below illustrates what ours sounded like. It was loud! The San Francisco Tesla service center was unable to fix it (grrrr), but I found several references to the product below in various message boards.
I ordered it and applied it to the rubber seal in the door (where the window slides up from) and let it dry overnight. The squeak is gone! Hopefully it stays that way!
You can order the product on Amazon (link). It was $11.55 USD when I ordered it.