I would rather you didn’t. Numbing creams can interfere with the application of the wax or, in certain situations, cause allergic reactions. For instance, somebody could be allergic to a benzocaine that contains an anti-itch formula without knowing it. They apply it before they wax, then become itchy. Thinking this is a reaction to the wax, they reapply the product, and therefore worsen the situation. Beyond this, I’m wary of using chemicals around such a sensitive area full of membranes and have heard horror stories of people not knowing a wax is too hot for their skin (our wax is kept at a steady warm temperature) because they are so numb. So, please avoid numbing creams or sprays.