Mich. Comp. Laws § 339.1217a

Sec. 1217a. Nothing in this act shall be construed to prevent a salesperson from demonstrating a product on the face of a customer or potential customer, if direct or indirect compensation for the practice, other than the sale of the product, is not received nor expected from the customer or potential customer. "Demonstrating a product" means applying to the face of a customer or potential customer only as much of a product as is necessary to demonstrate its correct use.