A packaging and dispensing device (10) comprising: a container (14) for storing a first fluid composition (38); a pipette (54) removably inserted in the container; a plug (110) removably assembled to a dispensing end (66) of the pipette, said assembled pipette and plug defining an inner compartment for temporarily storing a second fluid composition (114) isolated from the first fluid composition; and a pressure supply device comprising: a support (86) assembled to a second end of the pipette; a compressible chamber (93) in fluid communication with the second end of the pipette; and a pressure member (82) able to move relative to the support, between a first and a second configurations. The device comprises locking elements (92, 106) for maintaining the pressure member in the second configuration with an increased pressure in the inner compartment.