The WaterWieners™ inserts can be used with any of the Verspankens at varying temperatures by either warming them in the microwave or chilling them in the refrigerator. Combine temperatures and textures while discovering a myriad of stroking techniques to change up the experience and keep him speechless! Try the upward curl, rocking and swiveling or maybe the twist and since VërSpanken is an open-ended toy, cleanup is a breeze! It’s also great for couple play! WaterWieners™ make a great addition to any Verspanken purchase.