1. From your account page, click on the Manage Subscriptions tab from the Dashboard sub-menu on the left-hand side of the page. This will bring you to the All Subscriptions page, giving you an overview of your active (as well as inactive) subscriptions.

2. Locate the subscription that you would like to make adjustments to and click on Subscription Details. This will bring you to that specific subscription page.

3. On the left-hand side, you can see which products you are subscribed to, as well as the frequency of your subscription and your next ship date. To add a coupon code to your next order, click on the Edit Next Shipment tab, just above your subscription settings.

4. Once you are viewing this order's next shipment page, scroll down until you see the Add Discount box on the left-hand side. It's located directly above the Shipping Method selection option. 

5. Select the Add Discount option. A sub-menu will appear on the right-hand side of your screen. Input your coupon code into the Discount Code box and click on the Add Discount button to confirm.

Please note that coupon codes may NOT be stacked or combined for increased savings.