Just buy lube lol

or coconut oil

Neither, my pussy just makes free lube automatically whenever I’m horny

Vaseline is nothing like saliva. Take for example using it as lip balm, you certainly can’t use saliva for that!

It also works great to block hair dye around the edges of the hairline from staining the skin at all, and obviously saliva wouldn’t work.

Honestly I can’t think of any situation where you could substitute it for saliva, they’re in no way similar or compatible, completely different things.