How exactly should I apply it, and can I use it under clothing?

Apply the balm only to clean, intact skin on areas that feel stiff or tense, such as the lower back, shoulders, knees, neck, or calves. Take a small amount (a pea-sized portion to start) and massage it gently into the skin until mostly absorbed. Avoid eyes, mucous membranes, and any broken or very sensitive skin.

You can use it under clothing, but it's best to wait a minute or two for it to absorb into the skin to prevent transfer onto fabrics. The base contains oils, fats, and waxes, which could potentially leave grease marks on light-colored or delicate materials. Many people use it before rest or before going outdoors in cool weather, where it can be helpful under normal clothing. Always wash your hands thoroughly after application, unless you are specifically massaging the balm in with your hands, to avoid accidentally transferring it to your eyes or other sensitive areas.