I’m going to go ahead and put a disclaimer on this, so if you don’t want anything to do with Oviposition (it’s not, really, but it’s similar I guess??) then look away ig
I prefer my aliens with alien biology, personally, so I don’t really go by the human genitals headcanon and i try to stray a lil farther from the rest (they’re okay to have but im just not into them). So that said.
I headcanon trolls as having glowing baby gravy, meaning just that it is of a very dim luminescence and why is bc A. it’s pretty imo and B. I imagine the caves are fucking dark, dude, so
Trolls reproduce by storing material in a special organ, but it takes time to store, so it requires knotting in a sense, so you don’t just spill your shit out all over the place. In doing so, it’d prolly gestate for a span of a day or two and turn into what are called “packets” (see cephalopods/crustaceans) and then they expel them and put them in a bucket. I’m into ovi honestly but if you want a logical reason I’d say it’s bc it’s VERY hard to fake, so you couldn’t just nut in a bucket and be able to get away with not contributing to a totalitarian race concerned with the expanse of itself. Also easier to transport.
Average dick size on Alternia is anywhere from 10-16 inches given that I headcanon trolls as a naturally large race, as you’d have to be, seeing as everything else is fucking large there.
Finding partners who produce big ass loads is probably encouraged LOL
“Tieing” for trolls is a v v intimate process as a standard which means lots of cuddling and little affectionate gestures until the swelling goes and you’re f r e e