i'm not aware of anything you can put on it, i find the noise on mine to be fairly minimal, i doubt it would be enough to make a difference one way or another.
I have had a couple of Whisker Biscuits and neither one was noisy . I switched to a drop away mostly due to peer pressure and wanting to shoot FOBs . I havn't sold or given them away as I might want to revert back to them someday !
You lose 2-3 fps with the WB ..... Big Deal !
I never had an noise issue but I have heard of people using Conola oil on their arrow shafts to help make the WB quieter. I think they just dip thir shaft in a homemade tube full of oil and that helps keep things quite.