Lubricant/grease for de-noising rubber window seals?

Hey guys

I've had an annoying, feint sound coming from ear-level around my driver's door window, when I go over uneven surfaces. It's not loud, but it's definitely there and it's been a bit irritating.

I took the car in to get a few things checked out at service, and they said that sometimes a bit of lubricant can minimise those sorts of sounds. They applied it, and it does seem to have helped.

I asked him what type of product could be used for this, and he said he wasn't sure what consumer products were out there. So I'm wondering if anyone knows of a good lubricant product that's suitible for rubber door seals and which would minimise friction and hence noise?

Guessing plenty of people have had this sort of problem with their frameless doors, so I'm keen to hear your thoughts.

Thanks everyone!

Cheers
Mike