A dispensing device which ensures that a dispensing procedure cannot be initiated unless a firm coupling to a male coupling of a recipient is achieved is disclosed. The dispensing device comprises a coupling body, an inner flow sleeve, a release sleeve, at least one locking element arranged in a radial opening of the coupling body and a retaining collar axially movable between a first and second position. The dispensing device further comprises means for allowing axial movement of the release sleeve towards the dispensing end of the gun, and may comprise means for allowing axial movement of the inner flow sleeve away from the dispensing end of the device, when the retaining collar is in the second position.