>>16777468 (OP)
Interesting question. My theory is that as any society progresses it becomes more interested in having anal sex.
Anal sex was not unheard of in the old days, but it was rare. It was also usually condemned or at the very least frowned upon.
But as a society advances it usually becomes more wealthy, with higher standards of living and higher standards of education. This in turn results in a higher tolerance given to social dissent, human rights, and liberal values.
The net result is to confer legal protection to sexual deviants, advance feminism, and to neuter conservative forms of social control.
Consequently the incidence of sodomy increases at the same time as men become fed up with bitches who over value their own worth. Fucking an anus becomes the better option for many men.
Now extrapolating that trend into the future it is not unrealistic to assume that space faring civilizations may have become solely preoccupied with anal sex. A technologically advanced species may give over all reproductive duties to robot waifus, or they may simply have achieved a form of immortality where reproduction is no longer a priority. It makes sense then that some aliens may embark on interstellar journeys for the purpose of engaging in anal sex with novel species unlike their own.
Furthermore species in transient to sexual activity based upon sodomy, such as our own, will very likely welcome the prospect of wriggling, writhing, self lubricating, alien tentacles being forcefully thrust up our anal passages. Like this:
"Oh! Oh! OMG! AYYY! LMAO! HARDER! OH BABY OCTOPUS ! OHHHHHH! OHHHHHHHH!"
Porn producers the world over would certainly welcome the opportunity to make and distribute such material.
But personally I welcome the idea of having my anus sewn shut and pooing out liquid feces through my dick instead.
Anyway I hope this helps you understand.
