The invention relates to a method for introducing an application medium into a weakening gap (5) of a cover (4), such as a covering film or covering skin, wherein a cover (4) is provided which already has a weakening gap (5) formed completely over the length thereof on a first side (6), an application device (2) is positioned toward the first side (6), at a distance from the cover (4) and above the weakening gap (5), wherein a support is arranged in a supporting manner on a second side (7) of the cover (4), facing away from the application device (2), and an application of the application medium into the weakening gap (5) by the application device (2) is carried out. The invention further relates to an application device (1) for this method.