The ovipositor looks similar to a horse penis, with a "sack" beneath containing the eggs.
The lubricant produced by the ovipositor is similar to a water-based gel lubricant in texture. It also contains various sexual hormones, which induce the recipient to become more docile, crave more of the lubricant, and crave to be impregnated by egg-laying creatures. It also contains a compound similar to estrogen, meaning it can make people more feminine. Basically, the perfect recipe for being addictive and making those who drink too much, or get egg preg'ed, want even more. In smaller doses, it only acts as an aphrodisiac.
Their species is hermaphroditic, with all members being quite androgynous. They have two breasts with deeply inverted nipples which are perfect for small baby moth probiscus to reach inside. The "milk" produced is very similar to honey in flavor and texture. Iif the nipples are sucked on with enough force, they'll pop out, and look like long teats. If hand milked, they'd simply pop back in after being tugged a while, but if frequently milked with suction, they'd likely get much fatter and be permanently stuck out. If left inverted, the nipple could easily be fucked due to it's deep nature.
Due to the strong hormonal urges of their species, many choose to form a harem, or form one accidentally. In this harem, those with vaginas will have eggs laid in them frequently, and those with penises will fertilize those eggs. All will also be given heavy doses of the lubricant orally, which means lots of blowjobs for the moth. The members of the harem essentially become the leader's slaves, though due to the drug-like properties of the ovipositor lubricant they don't seem to mind it. Oh, also, they might have addictive pheromones too, because that's hot.
After the eggs develop, the larvae hatch from the eggs, and are basically just caterpillars. While normally the eggs are naturally ejected from the host shortly before hatching, sometimes they may end up staying inside, leaving the hole the eggs were deposited in teeming with the larvae, which naturally will want to crawl out. However, the the creature that fertilized the eggs was especially predatory, the larvae may instead choose to eat the host from the inside, which won't end well for the host.
If they were to cock-vore someone, their balls would produce enzymes that would lead to the breaking down of the prey's body into just proteins and stuff. While not exactly the same as semen, and not containing any sort of actual reproductive cells, the resulting thick goop would easily be mistaken for normal cum, in both taste and texture.

If all that sounds scary, don't worry. Moth can be equipped with more standard genitals too.