an applicator tip is provided for operating in conjunction with a pierceable fluid reservoir . assemblies in accordance with the invention can lead to an exceptionally easy to use , safe , and convenient system and method of applying a fixed dosage of chemicals to which a user might wish to avoid contact , such as parasiticides . the cap - applicator can have an internal piercing tip capable of piercing the reservoir when the assembly is converted into an active configuration . projections can be provided , in the form of fins on a tube or a multi - prong structure with straight or curved projections . the tips of one or more projections can include dispensing ports or the ports can be recessed from the distal tip , such as in a notch , so as not to be obstructed if the distal tip of the cap is pressed against an animal to dispense the fluid .