If you want realism, I suggest you watch something other than Star Wars. Short Guy is on the right track: Jabba is meant to be a sultan-type figure, lusting after and humiliating nubile young women. This is not hard SF.
Hard SF? Indeed. 
Now you make me wish that I hadn’t removed my joke about Jabba getting “fat” from an earlier post. 
Funny; as I recall, it was usually the reverse in Star Trek: human male (i.e. Kirk) attracted to (and attractive to) alien female.
Of course, I see now that you wrote “later Star Trek series”, but my gut feeling is still that male human/female alien pairings were more common than the reverse in all the Star Trek series. Anyone know if someone has taken the time to make a tally that would settle this?
I see nothing at all disgusting about having sex with Princess Leia. I’d do it.
Yeah, but would you let Jabba watch?
Hell, he can video tape it.
Yeah, but would you have sex with Jabba?
Would I have sex with… Oh! I see! Heh heh. I thought jack@ss was talking about sex with Leia!. So sorry. [sub]God, I’m embarrassed.[/sub] Please carry on.
Even Hutts need love. Or are you a Huttist?
“Jerry, I’ve come here tonight to tell my wife I don’t love her any more and I want to marry my true love, Jabba.”
HA! thanks for making my day
Perhaps you should rent Woody’s Everything You Always Wanted to Know About Sex (IMDB listing) and view the section (if memory serves, and it hardly ever does) "What is Beastiality?"Gene Wilder having an affair with a sheep wearing pearls and nylons is a scene not to be missed.
Jabba is a pervert, as others have said. He degrades people with whatever they find disgusting or horrible. Leia is dressed like a harem girl, but if Luke had been dressed the same way, he wouldn’t have been humiliated (I don’t think), it just would have been stupid. I’m sure that any sort of close physical contact with Jabba would be disgusting AND horrible for most folk, so he probably does that too–as suggested by “the scene where Jabba pulls the female Twilek close”–heck, just having him breathe on you would probably break most people.
And I have to agree: “Yurts” was a stroke of genius!