The case with a soft spiral-shaped grooves and the fantastic suction effect make the Tenga Flex so special! The flexible pleasure tunnel has different textures and different levels of tightness. The flexible outer sleeve?s spiral-shaped grooves move back and forth every time the sleeve gets moved up and down. The amount of stimulation can be controlled by how hard the person squeezes. There is a hole at the top of the toy. A finger can be used to control the suction effect. The pleasure tunnel should be removed from the outer case after use and be cleaned with running water. Then it should air dry on the integrated stick. A lubricant sample and instruction manual are included.