The following story was inspired by Ursula K Leguin's The Left Hand of Darkness.
It includes a character from an alien species which uses they/them pronouns.
After setting up the tent, I took a moment to relax, watching Everis bent over the camp stove. They fussed with the small gas flame for a few seconds before ripping foraged leaves into a pot of water. The tent filled with an overpowering scent of citrus and mint, the familiar nose-clearing top note of Everis' people's food. The herb, called the pitnee plant, was the Apallon garnish of choice, as well as a tea and much-needed insect repellant.
The Apallons were currently at war with a neighboring people, the Endols, and Everis, my travelling companion, had been outed as an enemy spy by someone they trusted - a former lover. Unfortunately, before being discovered as a spy, they had been an interplanetary diplomat: we both served as co-ambassadors to Earth. After working so closely, their betrayal automatically made me suspect, and I was far less familiar with the country's terrain - both physical and political - than Everis. My best shot at getting through the war with my head still on my shoulders was to stick close by them as we fled through the rainforests of outer Apallon.
When the tea started to fill the tent with vapor, I began to change clothes. One had to wait for the insects to clear out to expose even an inch of skin, or blood-sucking flies would instantly attack. I took off the netting headdress that protected my face, pulled off my gloves and sweat-soaked shirt, and wiped down my armpits and neck with a damp rag. The rag offered little relief in such intense humidity - jungle wetness with a pot of boiling water to top it off - but at least, feeling a bit less grimy, I could finally clear my thoughts.
"Do you need anything?" I asked. I sat on the tent floor, looking at Everis expectantly.
Everis was usually quiet, but they weren't one to avoid a question. But instead of answering, they averted their gaze. I swore I could see, in dim light filtered through the tree canopy and then the top of our tent, that they were blushing.
I let the silence hang. They stole a glance at me, and I saw their dark eyes, usually inscrutable, looking up and down my body. I had suspected for a while now that something was the matter, and I decided to be direct.
"Are you... are you in heat?"
Heat is our best human translation for how the people of this planet, Vera, procreate. The Veran body - Everis' body - the majority of the time, is neither male nor female. Both genitalia exist in a latent state similar to what would be seen in a human fetus around 22 weeks, but completely internally, inside something similar to a kangaroo's pouch. They undergo a cycle lasting about 100 days. For the first 60 days or so, their body is receptive to pheromones from compatible partners. This causes them to in turn release their own response pheromones causing the genitalia of each partner to begin to differentiate into either male or female.
Once that receptive period is over, they undergo something akin to a mega-accelerated human puberty, soft tissue shifting, breasts budding for the female, widening back and shoulders for the male. Only after the changes have occurred do the people of Vera enter their fertile period. A spike in hormones causes intense arousal, and when an unreciprocated heat occurs, it can be torture.
I knew this all from my research into Vera and its people, but I had never been close enough to a Veran to really know what it was like. The clothes they wear are loose and betray little of the changes that occur throughout the cycle, and the only hint I ever saw of a heat was just that clerks in the embassy would occasionally take a few weeks off with no questions asked. Everis hadn't shown any signs as far as I could tell, but their usual perfectionism had been slipping lately. A knot tied wrongly there, a rusty, unwiped blade here.
My question hung in the damp air as Everis stayed silent. I knew that meant yes. I didn't know what else to say, but they looked upset, which tugged at my heart. I had never seen them be flustered before. But they would never ask me for help in such matters, being human.
Everis went back to the food as I continued to give myself a work over with the rag. I pulled my socks off and rubbed my feet, then my legs. I tried to ignore Everis becoming increasingly clumsy, but when they dropped a piece of meat on the ground - one we'd spent hours hunting - I had to say something.
"Something is wrong. You're in heat. Why?"
Everis finally looked at me. They took a steadying breath.
"Your presence - your maleness - may have caused me to enter my heat early. I don't - it's strange. Different from my other heats."
"Different?"
"I... I'm not sure. I feel different. I haven't changed correctly."
"You need help. I know this is painful for you."
"I... I can't accept this. You can't..."
They trailed off, staring at me. To be totally honest, my cock, already hanging low in the heat, had begun to respond, firming up inside my pants. I had been in a long dry spell since I arrived, since most people on Vera were disgusted by me. My constant maleness was seen as a perversion of nature. Everis usually seemed to find it dryly funny - imagine, someone who was always male! - but today it clearly wasn't so funny at all.
They swallowed. I moved toward them, taking their cool, gloved hand in mine. "I don't mind. I can do this for you. I - I've done this, with my own species. I want to help you."
Everis pulled away, shaking. I was about to retreat, but they began to pull off their own gloves and shirt.
I have to admit I stared. I had seen diagrams and artwork of unclothed Verans, and occasionally some at bathhouses, but never closely, never in heat.
Everis was beautiful. They were short in stature compared to a typical adult human, but elegantly proportioned, with wide hips and a dimpled stomach. The stout figure they made under clothing belied soft muscles that rippled in vaguely unfamiliar ways with each movement. The skin on their torso was the color of sand and dusted with fine brown hair. They had four small breasts with small, deep brown areolas. Markings on the sides of their torso and shoulders gradated smoothly into dark brown arms and legs. Their sternum was etched with red tattoos, indicating their phase of life, birthplace, and lineage.
I moved closer so I could feel their chest. Everis sighed. Their skin was soft and yielding, and they moaned softly when I grazed a nipple.
"I - this, this is not normal," Everis breathed.
"What isn't normal?"
"My self. My body... see for yourself." Everis looked up at the roof of the tent, flushed with embarrassment.
I tugged down their pants, revealing their genitals. The skin around their groin was deeper than the surrounding skin, purple to almost-black. A small fertility sigil was tattooed on their right hipbone. A firm penis, small enough to just fit in my hand, stood out of their fluffy bush of pubic hair.
"So you developed a penis and breasts? That's not normal, right?"
"Some of us do grow breasts in heat, regardless of sex. You- you will have to go further."
I rubbed their penis, gliding the skin of it up and down like I would have my own. Everis shut their eyes and pressed their lips together, exhaling sharply. Clearly there wasn't any issue there, so I ventured a finger between their legs.
