Fantastic Arousal: As I may have mentioned before, not everyone keeps their genitalia in the same place, and likewise, not everyone keeps their erogenous zones in the same place. (Or even in the same plane of reality. Like, say, AIs with unusual cognitive maps whose erogenous “zones” include things like n-dimensional geometric figures, but only if they include ratios of Mersenne primes.)
There is also the matter that they aren’t all sensitive to the same things, too. For example, those engaging in interspecies relationships with the kaeth, whose thick, multilayered skin contains an awful lot of metal – especially where the dorsal plates are concerned – and are not themselves members of remarkably kinesthetic species may well be advised to bring some power tools to the bedroom.
And, um… use protection.
Bizarre Alien Sexes: While the eldrae started out with the standard two (male, female), biotechnology has since added two more to their repertoire (neuter, hermaphrodite). And the standard taxonomy of sexes in their language, which has to cope with other species, includes two more – the most common mappings of other-species sexuality (prenuptial catalyst, postnuptial catalyst). And the language allows for an arbitrary number of other gender affices, because while most species can fit into that six-gender system, usually having no more than four and the mode being two, the one-to-couple-of-dozen-variants spread in how species divide into sexes means that… well. Yeah.
Querying today’s new catalog entries in category:erotica; displaying (8) highest-rated results:
Meiose With Me
An esseli bioengineer rediscovers the wonders of sexual reproduction.
Naked Singularity: When Particles Collide
Those naughty, naughty particles.
Prompt Criticality IV
Further unbounded lust among the orgiasts of the Atomic Age.
Ricatra Today: Vol. CCXLVII
The galaxy’s finest xenophilia.
Thrusters Firing! 2: Engage the Retro-Rockets
The microgravity adventures continue.
Tunnels of Love
In the mines of the Mohorovicic, the passion runs as hot as the magma!
Warm, Sticky and Moist
Hilarity ensues when virtual lovers meet in the flesh for the first time.
You Spin Me Around
Erotic-comedy star Lalíríë Celestial discovers the Coriolis effect.
Zero-G Spot: If there’s a couple anywhere in the Empire that hasn’t, ah, joined the 100 Mile High Club, it’s because they haven’t yet finished treatment for a case of galloping cosmophobia. Sure, there were some special requirements to figure out w.r.t. anatomical docking maneuvers (mostly involving conservation of momentum), but that’s why they did science to it.
As for celestial polyamory, insert your own three-body problem joke here.
Screw Yourself: A remarkable percentage of people who have access to forking technology try this at least once or twice, with or without gender-flip, just to decide if that qualifies as sex or masturbation.
(Hint: it’s sex. Narcissistic, quasi-incestuous, oddly symmetrical sex.)
Sex By Proxy: The slinky (i.e., recorded full-sensory and emotional data) erotica market. Also, possible by techlepathy (see: Psychic Powers) if you have the consent of the people you’d be eavesdropping on.
Also, in a more friendship/romance-oriented way than strictly sexual, a consequence of the metamind feedback system mentioned in Touched By Vorlons, and, relevantly, Angel Unaware. If a lot of people like you (or one person’s liking, or indeed love, is particularly intense), this feeds back into the metamind’s opinion of you, which in turn feeds back into individual’s opinions of you… which then leads to people liking, or at the very least being predisposed to like, you even if they’ve never actually met you personally. As A Miracle of Science puts it, “Brazil has decided you’re cute.“
Naughty Tentacles (since removed from TV Tropes, but I think we all know what this one is about, yes?): Given that there are species with tentacles, and Boldly Coming is in effect, this does happen (consensually). However, no-one out there would understand why humans in general and the Japanese in particular are so obsessed with it, nor would those involved appreciate the interest in their sex lives.