An apparatus, comprising: a stem consisting of a single unitary element and comprising a lumen extending from a proximal end toward a distal end, the proximal end including thread structure capable of coupling with luer-locking structure of a syringe; and a nasal stopper consisting of a single unitary element, the nasal stopper being affixed to the distal end of the stem; the combination consisting of the stem assembled to the nasal stopper is operable as an atomizing nozzle, wherein the apparatus further comprises: first cooperating coupling structure (170, 172) carried between the stem and the nasal stopper configured to form a distal fluid seal to resist leakage of fluid from the lumen; and second coopertating coupling structure (176, 178) carried between the stem and nasal stopper configured to form a primary torsion-carrying connection; characterised in that: the nasal stopper comprises a structure arranged to permit insertion of a distal end of the nasal stopper into a nostril opening of a human, and to resist over-insertion of the distal end of the apparatus into the opening; wherein a proximal portion of the nasal stopper comprises a shield configured to resist over-insertion of the distal orifice into the opening, the shield comprising a frustoconical surface and defining an open-ended shell structure having a proximal end being configured as an open cantilevered free end. a stem consisting of a single unitary element and comprising a lumen extending from a proximal end toward a distal end, the proximal end including thread structure capable of coupling with luer-locking structure of a syringe; and a nasal stopper consisting of a single unitary element, the nasal stopper being affixed to the distal end of the stem; the combination consisting of the stem assembled to the nasal stopper is operable as an atomizing nozzle, wherein the apparatus further comprises: first cooperating coupling structure (170, 172) carried between the stem and the nasal stopper configured to form a distal fluid seal to resist leakage of fluid from the lumen; and second coopertating coupling structure (176, 178) carried between the stem and nasal stopper configured to form a primary torsion-carrying connection; characterised in that: the nasal stopper comprises a structure arranged to permit insertion of a distal end of the nasal stopper into a nostril opening of a human, and to resist over-insertion of the distal end of the apparatus into the opening; wherein a proximal portion of the nasal stopper comprises a shield configured to resist over-insertion of the distal orifice into the opening, the shield comprising a frustoconical surface and defining an open-ended shell structure having a proximal end being configured as an open cantilevered free end. first cooperating coupling structure (170, 172) carried between the stem and the nasal stopper configured to form a distal fluid seal to resist leakage of fluid from the lumen; and second coopertating coupling structure (176, 178) carried between the stem and nasal stopper configured to form a primary torsion-carrying connection; characterised in that: the nasal stopper comprises a structure arranged to permit insertion of a distal end of the nasal stopper into a nostril opening of a human, and to resist over-insertion of the distal end of the apparatus into the opening; wherein a proximal portion of the nasal stopper comprises a shield configured to resist over-insertion of the distal orifice into the opening, the shield comprising a frustoconical surface and defining an open-ended shell structure having a proximal end being configured as an open cantilevered free end.