Creating a wet look can be fun, but the hard part is creating a look that looks wet without your client actually having to reapply baby oil or lotion over and over. Or even worse, drenching your client until they look like a sad wet dog.
The simple solution for creating a nice even wet (or sweaty look) is glycerin and a spray bottle with three parts water to one part glycerin. When using water alone, the moisture is gone before you even know it. Baby oil works for a bit, but after about 5 minutes you find that you have to reapply. With glycerin you can also achieve a shiny look that looks wet without it dripping everywhere.
Glycerin can be found at almost any drug store for under $10! To find the right solution for your shoot, play with the ratios of water to glycerin and spray away until you have your desired results!