Well…she’s not THAT alien!
Haha. I guess too many alien traits all together might push it over the top. Wings would be okay, and maybe tail or scales or something. But a non-human face just pushes it into weird territory.
Before reading this thread I probably would have called myself a science fiction fan, but I am not sure that I am allowed anymore as I honestly never considered this question. The only thing that I really have to contribute (besides the shame of my lack of devotion to the genre) is that it the first thing I though of when seeing the thread title was this comic.
Fool! Don’t you know after (sometimes even during) sex a shapeshifter will inevitably change back to alien form and kill you!
Funny, I don’t think pedantic is the word you should have picked, either 
Quite a bit of furry art is devoted to variations on the centauroid body plan: four legs supporting a primary torso, then a secondary torso with arms and head. The name of one such fictional species, the Chakat, has become so widely adopted as to now be nearly synonymous with the felinoid versions. Would anyone consider going that far?
I could go with a little slime… it’d depend what it tasted like. Lime jello would be nice. 
Tentacles are a maybe… the Thermians were just such nice “people”.
I agree with Miller that it would largely depend on the individual alien… but that said… scarab beetle heads would be just too damn freaky no matter how good her personality was. shudder
Yep, although I’d make an exception for the Malmooth.
I’d be less concerned about form than I would want to know about mating habits/rituals. I do not want to be stuck in the position of playing the male for a preying mantis courtship.
Them green Orion slave woman were among the first adolecent boyhood phantasies.
But I read some sci-fi book were the human male gets on an alien built eco-system ship, and falls for a centaur type female, and ends up banging her. Umm… no thanks. I have no bestiality hunger within me.
She gives good head.
Marc
Umm…Horta. Doesn’t talk, right? Stone cold, yes? And made out of rock?
I think I dated one or two of these…
Assuming the “centaur type female” is sentient I’m pretty sure that “bestiality” isn’t the appropriate description… “miscegenation” I might buy, but bestiality suggests one partner is a lower order animal.
That sounds like John Varley’s Titan. The centaur types were called Titanides, their clans were set up on the order of the Modes of medieval music, and they didn’t even come CLOSE to male/female…there was some kind of complex interplay between something like three or four different genders, involving egg swapping or something like that.
Or possibly Jack L. Chalker’s Well of Souls series.
So radial symmetry is OK then?
So long as she’s a cute xeno-echinoderm. 
I always wanted to rock Cassandra ‘s world (Leslie Bevis)… ever lovin’ Newcummer Alien Sex.
Alen Nation had some hot Slags.
Wot. She was cute. Not.
[At which point I read what I have written and realise that my screen name is working against me here.]
On that topic, though: despite the mild controversy when Captain Jack was introduced, it always seemed to me that he was nothing more than an obvious extrapolation from Captain Kirk. After all, anyone who is willing and able to shag an alien is hardly likely to turn his nose up at half the members of his own species, is he?
So all that slash fiction is probably right on the money.
It depends on the alien. (I’ve mentioned before that I have a love for tentacles.)
If we’re talking the Doctor…he could regenerate into a GIANT FREAKING SIVLERFISH and I’d still do him. His current dreamy looks are just an added bonus on top of - heh, no pun intended there - a wonderful personality and intellect.
As for the aforementioned Captain Jack, he does nothing for me. Cute, check. Open minded, check. Personality, check. Intellect… Nope; he acts like a teenager. Feels like jailbait. Can’t do it. He can hold the camera for the Doctor and me though!
No bugs or squid-faced people. Otherwise, I’m pretty open.
Wings? Sure. Fur? Hell yeah. Tentacles? You betcha! Extra limbs? Why not? But there needs to be a face I can relate to.