Lately some of the video producers have been complaining about an over saturated video market.....so they probably won't help you.
If they do, kudos to them, that's how capitalism should work! Don't be afraid of competition if you're confident in your art/product.
I believe when you sign up to clips4sale to open a store, you can get copies of model consent forms from them, but I'm sure you can find some online.
(I'd sign up with clips4sale first, since it's obviously best to use their forms......since you never hear stories about producers being shut down there.)
They probably also provide you tax info/forms there also, since they're the ones who'll be sending you the checks every month.
If/after you get successful and want to start your own site, you'd probably have enough money then to have a meeting with a tax lawyer or business lawyer to get more detailed info.
(Normally I hate lawyers, as do most Americans except the sue-happy evil Americans, but talking to any professionals about anything usually helps alleviate concerns, since they know
what they're talking about. (This usually sets off the trolls who'll whine that they DON'T know what they're talking about, but there are mechanisms in place to watch over those folks, whereas the internet has few to none to watch over the people who claim they know what they're talking about....))
You can always do Google searches on your state's laws, but you may need a lawyer to interpret them for you! Or do some research and find some office where you can talk to someone.
Do you tell them you're making tickle videos? I honestly can't tell you, but I've been thinking recently - there are hundreds if not thousands of clips4sale stores. There's only 50 states. There are millions more porn sites, from a girl dangling her heel while wearing stockings, to hard core sex all the way to faked rape scenarios. I wonder how easy or hard it'd be if you just walked in the tax office at city hall and just said "Look, I'm making a company that sells girls being tickled. I want to pay my taxes. How do I do everything right so that the government gets their money?"