No insertion and this attachment is frequently used w/clothing on.
The Smooth FlatTop is the only attachment that allows a user to sit on Sybian in either direction to customize where you want the vibration and hump to come into contact with your body.
There is no latex in Sybian parts. All inserts are made of a material known as Dynaflex which is a TPE Compound and Kraton. No allergic reactions have ever been reported. The insert is beige flesh coloured.
Water based lube is recommended with these inserts.