The invention is directed to an insert system comprising an insert with a base and an outer skirt extending from the base, thereby forming a chamber. The outer skirt is provided with a first inner skirt surface and a first outer skirt surface. The insert system further comprises a panel with a core structure and a first cover sheet that at least partially covers the core structure. The first cover sheet defines a first outer panel surface and has an opening. At least one piston is arranged in the opening and beneath the first outer panel surface. According to the invention the piston during mounting of the insert sweeps into the chamber to discharge an adhesive agent from the chamber into the core structure via at least one pathway.