3 girls - biological or not - are not sisters by blood but sisters by heart! You're wondering how to say "I love you sister" in the most special and memorable way? A piece of cake! Welcome to the world of creative, unique, sentimental, and practical gifts for sister at Gossby. We have a little bit of everything for every type of three girls BFF, from gifts for sister in law to top 10 birthday gifts for her. Among these awesome sister gifts, our custom coffee mugs have always been a best-seller on sister birthday. Customize up to 3 girls with hairstyles, skin colors, clothes, drinks, and quotes to make your personalized mugs stand out.