The Wooden Shoe
This little shop is probably the filthiest sex shop you'll ever encounter. If the windows of this shop don't already give it away, you'll find the dirtiest porn in this shop of all kinds.
They also sell toys, lingerie and all the other things you might expect from a sex shop.
As a bonus this shop is called the Wooden Shoe, discretely enough so nobody else has to find out what you did in Amsterdam.