I use my own foreskin and precum. As for getting in on the cut/uncut needing lube debate, there are cut guys who do 'need' it, using the term loosely to say they require it for a much more enjoyable masturbation session or else risk possible chafing or just being too dry for a good pleasurable wank. As for me, I am cut and have never needed lube, loose cut though and am restoring my foreskin. Call me a militant anti-circ as someone said on here or whatever, I have my own logical reasons of natural existence being preferred on that path. However, I say as long as you perform to your own standards and are happy with how you do it, then that's what matters.