Tiers of alien junk

Tier I: Conventional but quirky (e.g., retractable, prehensile, comically large, etc.)

Tier II: Unfamiliar morphology (e.g., tentacle dong, can impregnate at range, etc.)

Tier III: Unfamiliar function (e.g., apparent dong is actually ovipositor)

Tier IV: Unconventional vector, material (e.g., can impregnate via kissing, holding hands, etc.)

Tier V: Autonomous reproductive apparatus, discrete (e.g., junk is separate or separable organism that goes scuttling about looking for mates)

Tier VI: Unconventional vector, immaterial (e.g., can impregnate via telepathic contact, energy transmission, etc.)

Tier VII: Autonomous reproductive apparatus, distributed (e.g., impregnates via architecture, by cultivating gardens whose produce the prospective mate must consume, etc.)

Tier VIII: Unconventional vector, abstract (e.g., their reproductive organ is their name and they can impregnate you by tricking you into saying it)

Bonus Tier: That`s no junk (e.g., apparent dong is actually defensive organ that shoots laser beams)

(Note that we are concerned here solely with the morphology and function of the junk in question. The organisation of reproductive duties is a separate axis; for example, a species of bee-like aliens might have a queen and a discrete reproductive caste responsible for impregnating her, but the actual deed is done via conventional tab-A-in-slot-B mating, placing them at Tier II at most.)