Collection of biological fluids. At least some of the example embodiments are methods including: placing a lower mold component, the lower mold component structurally defines a negative image of an insertion end of a polymeric sleeve; stacking into mating relationship a first disk member, the first disk member structural defines a negative image of an anterior volume vented to atmosphere on the insertion end of the polymeric sleeve; coupling a rod member to the disk member, an exterior surface of the rod member defines a negative image of a main passageway through the polymeric sleeve; closing an outer mold assembly around the rod member, an interior surface of the outer mold assembly structurally defines a negative image of an outer surface of the polymeric sleeve; and injecting a polymeric compound in a liquid state into the outer mold assembly.