The present invention is directed to a fluid-imbibing dispensing device for the initially delayed delivery of an active agent to a fluid environment of use and to a method of using the dispensing device. The dispenser comprises a housing having a first wall section and a second wall section in reversibly sliding telescopic arrangement with each other, which housing maintains its integrity in the environment of use; an internal compartment surrounded and defined by the housing; at least one active agent formulation in the compartment; and expansion means and a push plate in the compartment for separating apart the first and second wall sections of the housing after exposure to the environment of use to expose the active agent formulation to the environment of use.