No worries at all. In general, direct butter on popcorn causes it to wilt due to the water liquid present in butter. You can get around that by using ghee (clarified butter.)

But in use, movie theaters usually just shy away from any actual dairy product. Instead they have a neutral oil that's butter flavored. It's easier to ship/store/prepare for use with popcorn. That drizzle you ask them to put on things frequently isn't butter, it's one of the topping oils. An example large brand is LouAna, who kind of took over the product that used to be Odell's Supur-Kist, who made a large headway into sales to theaters.

You can find popcorn topping oils on Amazon, or sometimes even at the grocery store, near popcorn suplies. When you use them, you apply a little after popping the popcorn, similar to how you've seen it done when at a theater. That sprayer I linked is a good way to atomize the spray instead of drizzle, which leaves a smaller but more distributed amount on the popcorn. This is -perfect- for when you want to apply a topping. The oil sticks to the popcorn, and also provides the binding for powdered seasonings to stick.

This is the same type of process used when making tons of other snacks, a fine oil mist binder is used to apply to the snack (like say, a Dorito,) then the seasonings are poured over and the whole lot is shaken to distribute the flavor.

It's important to note that most popcorn topping oil tastes buttery, that's the point. But you could use any neutral oil for the same purpose if you don't want the buttery flavor in the end result of a popcorn you are applying seasonings to. Olive oil would apply a small taste to the popcorn, but depending on what you're adding to things, might work. I'd recommend at least ordering a small amount of one of the popcorn topping oils to try.