Applicator apparatus can include a circumferential wall and a support arm movably mounted relative to the circumferential wall. The support arm can include a protrusion extending in an axial direction within an interior passage of the circumferential wall. Methods of assembling the apparatus are provided in further embodiments. Methods of introducing an additive are provided in further embodiments. In further embodiments, a mouth fill device can include a circumferential shroud. In some embodiments, a plurality of apertures can be disposed in a circumferential lip circumscribing an end of the circumferential shroud. In further embodiments, a protrusion can be mounted relative to the circumferential shroud. In further embodiments, a collapsible container or a collapsed container can include a first shell, a second shell, and a circumferential bladder that can have a higher axial collapsibility than both the first shell and the second shell.