Although the flipbook says on your next walk-in, most likely it means that you will have to walk-in a Macy's store to get your bonus. However, it is expected that these can be stackable like the previous promotions. This means that if you have a lot of ShopKick points and repeatedly redeem for $5 Macy gift cards, you will repeatedly receive 200 Bonus Kicks for each gift card redeemed.
Additionally, after you get all your bonus kicks and walk in a Macy's, all these bonus kicks will be stacked on top of each other so that you do not have to do multiple walk ins at Macy's to receive each one. So for example if you had received 3x 200 Bonus Kicks, the next time you walk in Macy's, you will receive the amount you are scheduled to receive before/after unlocking the extra points in addition to 600 Bonus Kicks (3x200 Kicks). As a result, if you typically use your kicks for Macy's gift cards, today would be the best time to redeem them. This offer is only valid on 6/29 and the walkin bonus are valid between 7/1-7/28.