Apparatus is described for use with a container (102) for dispensing a composition (112), the container including a movable platform (106). The apparatus includes a container holder (101), which includes: an upper portion (116), which includes one or more user input elements (104); and a lower portion, including a driving unit (201, 3001) and a power source (205, 3008). The power source (205, 3008) is operative to drive the driving unit (201, 3001) to move the movable platform (106) of the container (102), in response to actuation of the one or more user input elements (104). Other applications are also described.