You should advise your client to NOT use any commercial bar soaps either prior to the session and afterwards. Especially Dove soap, This is the worst thing to use and will cause the tan to fade and become patchy. It can also leave an invisible film preventing development of the spray tan. Most times when a client has an issue it is the result of using Dove or a commerical bar soap prior to the session.
Advise your client to also refrain from any exfoliating soaps or body washes. We recommend they use our Glow Care luxury body wash. It has been formulated for spray tanning and is free of SLS and drying alcohols. They can also use it in lieu of shaving cream. https://shop.yourperfectglow.com/Wholesale-Self-TannersAftercare_c_35.html