I agree with you, that I don't think that Didi has developed any mixed emotions (or jaw cramping) due to eating Zii out, yet. Although it is worth talking about.
One has to remember that Didi's previous lovers, with few exceptions (Matt namely, and Gary recently), did not have a lot of stamina. They were unable to satisfy Didi (due to her psych. issue), but they themselves were able to triumphantly climax while they rode the Didi train. {Well, the last part I assume was true in Matt's case barring hallucinations of Gary or hot sauce incidents or errant groin kicks, otherwise I am unsure if he would have wanted to keep trying with her.} Lovemaking for Didi was a struggle for her but never for her partner. She is certainly very giving to those she likes (e.g. pancakes, delicious dinners, and dessert cakes for instance). I can see her 'putting out' and suffering with some TMJ discomfort as a way of showing her love to Zii. She certainly wasn't shy with bedding her previous male lovers. I guess we'll have to see if she complains about missing the feeling of a man's Star Power, or if she doesn't find that much satisfaction in oral sex with a woman, or if she brings some of the blended orgasm toys to Zii's bed.
I have to wonder: how long have those two been at it? If Didi is complaining about giving her oral sex, does Didi just not realize how much time has truly transpired? Is Zii taking a while to orgasm, due to emotional conflict or stress or Didi's lack of skill? I mean, she obviously doesn't have a watch to look at down Zii's nethers-way {market for belly-ring LED clocks?} TBH, I expect Zii has came at least once and she's greedily accepting Didi's oral skills... at least until Sonya comes back home.