Applicator and assembly comprising such an applicator

Applicator (2) for applying a composition on the human body, comprising: - a support (10) configured to be mounted removably on a device (3) that allows to transmit a movement, - a reservoir (18) secured to the support and containing the composition, this deposit delimited at least partially by at least one sealing element (15) being - a supportive engagement element (11) of the support at least during use, - an element opening ( 28) able to act on the sealing element (15) in order to put in communication the reservoir (18) and the applicator element (11), characterized in that the opening element (28) is placed on the bottom of the tank and arranged to exert an action on the sealing element (15) when exerted on the applicator element (11) a sufficient pressure that tends to introduce the sealing element (15) inside the reservoir (18).