I FEEL WEIRD TYPING THIS OUT BUT because i want to have some fun with a bit of xenobiology, i headcanon that allura has not only a vulva, but with heavy arousal she can also grow an ovipositor from where a human would expect the clitoris to be. this can be attributed to Allura's shapechanging abilities, and therefore this appendage is entirely optional in smut threads.

it very much resembles (NSFW IMG) these kinds of ovipositor toys and the colour of it is a dark, dusky pink. it's also probably like, average-length.

the act of oviposition (egglaying) is optional, as-is knotting. she's a magical alien after all ¯\_(ツ)_/¯