A device for inflating and sealing an inflatable structure, such as inflatable cushions is disclosed. The device includes an inflation assembly configured for inflating a cushion cavity of a film material with a fluid such as air and a sealing assembly comprising first and second assembly portions configured for receiving and sealing overlapping portions of the film. A disengagement mechanism is associated with the first and second assembly portions for moving the first assembly portion relative to the second assembly portion for reversibly disengaging the portions for releasing the pressure therebetween.