Some ideas for sci-fi erotica things
Two only two people on an entire planet, marooned and struggling to survive. Basically The Martian but gay and horny.
The crew of an interplanetary freighter who spend months together while hauling cargo through the emptiness of space.
Zero gravity sex.
Someone who's part of a spaceship crew, meets someone in a spaceport bar and has a 72 hour romance.
Two people stranded in a rover on Mars during a dust storm.
The only two people awake on an interstellar spacecraft, which won't arrive at its destination for years. Basically Passengers but gay and horny.
The largest city on this planet, and you only just got here. By chance, you meet someone who might be able to show you around.
A long distance sleeper train, travelling across a planet's hostile surface. Two strangers are sharing a room. Then the train breaks down.
Two people trapped in an spaceship escape capsule, waiting for a rescue crew to arrive. The emergency message said it could be hours. And these two have some issues to work through.
An abandoned crater town on the Moon. Two people arrive on an urbex trip. But why is this place abandoned? And are they really alone here?
The only two people on the far side of the Moon, and the strange feeling of loneliness it brings.
Everyone on this spaceship is dead, except these two. Now they need to figure out what happened and how to save themselves.