Is sexuality among the aliens as enjoyable as it is among humans?
Is it repressed and censored as like on our planet, or openly and freely celebrated? Is there a system of marriage?
It is not exactly accurate to speak for all worlds at once so generally, and there are more and less differences between all races, of course.
However, sex is natural to and enjoyable to all races of people.
Advanced races do not have any of the kinds or degrees of repression and censorship in any subjects the way we have on our world.
Advanced races truly value the commitment to a partner (marriage) and the structure of immediate and extended family.