Why do you think Jocelyn looked at Luke like “she didn’t know what her body could give her” when they made love in “Who the wolf loves”?
I remember reading your question and chuckling bcoz it's such an amusing question but at the same time, a thought inducing one! And Ik I'm pretty late to answer this one (oops, sorry) and some points in my answer could be similar to the ones others already put forward (I've still tried to take those theories out but yeah give or take a few I guess)
I recently saw a post by a mutual who wondered if this was bcoz Valentine was bad in bed (which was funny as hell ngl) and that was my first answer (just to be sarcastic lol) but come on guys, Jocelyn openly admits to Clary as she narrates her story in Cog that-
“Clary,” Jocelyn said. She sounded tired. “We were happy. At least for the first few years.
So I don't think Jocelyn was unsatisfied as such (Guys, stop spreading the propaganda that Valentine performs poor sexually 😭 it might make him jump right back from his death; ik he's already rolling around in his grave rn/ just kidding) and that it was described so bcoz of many other reasons-
Alright, first and foremost, let me give the most obvious and probably the most boring one you've heard yet (and the one I believe in most as a med student myself) reason for why I think Jocelyn reacted like that- her pregnant state/her pregnancy hormones. Though it's not been explicitly stated by CC, it's pretty clear that the Nephilim are essentially like the mundanes when it comes to biological processes and physiology. Atleast, when it comes to the topic of reproduction or fortification. And if that's the case, there's no doubt Jocelyn gave that response, because generally the libido of a pregnant woman may (keyword, may, this shouldn't be taken as a definite set point since human bodies show a LOT of variation) show increase in the transition period between her first and second trimester (which is what I believe Jocelyn was in at that point i.e she must be atleast 3 months pregnant) due to hormonal changes (rising estrogen and progesterone levels) and along with increased blood flow to the pelvic area, she would experience heightened arousal, sensitivity and ultimately, lead to more intense orgasms. So yeah, I think it makes sense why Jocelyn felt surprised that her body could be pleasured so much while having sex. (Source material- NIH/National Library of Medicine; I will drop the exact link of the research article if someone requests it/wants to refer to it)
Now the question arises, why did she not feel the same way while she was pregnant with Sebastian and still married to Valentine before? Again, all we can do is theorise atp bcoz there's nothing explicitly said, but I personally think that it was because of the demon blood and of course, jocelyn's depression (I'm gonna talk about it later). Jocelyn tells that her first pregnancy was horrible- with all the nightmares and stress she continually felt, I don't think she must have been very enthusiastic to participate in sex at all, and if she did, again, I don't think her libido was just as high or that she was in the mental state to enjoy it. So yeah, this brings us back to why "she sounded almost surprised, as if she had not known or imagined what her body could give her."- as in, she didn't know that her body could even feel this pleasure in the state of being pregnant, as if she'd never felt this aay before in the past, the same situation.
There's another thing that could've led her to act so- The Angel blood™. Valentine claims that he started mixing powdered angel blood in her food secretly (srsly Valentine when are you gonna stop spiking edibles Bud 💔, to think you would've learnt your lesson by now) which had positive effects on Jocelyn, giving her motivation and a sense of well-being (acting as an anti depressant to sum it up) so yeah, Jocelyn's pleasure as she orgasmed could've been elevated because of the angel blood already present in her body, I don't believe it was such a pleasurable experience for her solely because of the Angel blood but yeah sure together it could've created some synergistic effects maybe?
Secondly, I think the aspect of her mental space should be considered. Even during her first pregnancy, she seems to be suffering from clinical depression which was mostly triggered by Luke's supposed death. This, combined with the after effects of the demon blood that she was being injected with, must have severely impacted her sexual desires etc etc, and in this case, they're both relieved in a way that everything is finally over (context: the conversation they had just before they kissed each other) so yeah basically Jocelyn is just in a different mindset at that moment, she's relieved and relaxed from the continuous immense stress that she was under previously- honestly a lot of factors come into play here but primarily, it could be because she was feeling a lot better overall- mentally and emotionally. (Yeah, yeah ik that she was miserable bcoz she'd lost a huge chunk of her life and her son but figuratively speaking... Her own situation at that moment was better than it had been before the uprising)
Thirdly, I think it was because she was probably using sex as a way to escape (Jocelyn is a character whose first instinct in any problem she faces is to run from it or have a flight response), and it seems to have worked perfectly! As in, the pleasure she felt could be a mode through which she released all her stress and in the aftermath, "she sounded almost surprised, as if she had not known or imagined what her body could give her" because it must have felt really good for her.
Lastly, based on whatever CC has written so far, smut scenes written by her cannot be taken as being exactly realistic or reliable bcoz they contain little to no foreplay (most of them anyway) and Luke was basically inexperienced in this scene so I don't think he even knew what he was doing (since sh are known to be a conservative society) it's not realistic of him to have a great sexual prowess, definitely not more than Valentine (who was a married man even if we consider he was inexperienced before marrying Jocelyn- which I don't rlly believe btw I mean come on, it's Valentine we're talking about) so I don't necessarily think Luke was any better at it than Valentine could've been.
There are many more reasons too, I was influenced by other posts to this same question that my mutuals answered and yeah, a lot of them make sense too- like for example, Valentine being a narcissist was not actually attentive to what Jocelyn wanted or he wasn't much on the giving side of the scale when it comes to pleasure, or that he used sex as a weapon of manipulation and that Luke was unselfish in his affection (he wanted to pleasure Jocelyn without expectations) like he says in the letter-
"I wanted to please you more than I had ever wanted anything. I wanted to make you cry out with it"
There are others like Luke was probably hyping himself up or didn't know how a woman would actually react during sex so it could be that in his understanding it was so, I mean we totally cannot remove all the possibilities of him being an unreliable narrator.
And there are ones that are my favourites just because I'm biased towards Luke (The hc of this happening bcoz Luke was absolutely HUNG like a horse- all courtesy of @jonathanspenguinboxers ) and many others, I won't repeat them but surely yeah, they all make sense.
All in all, I don't pinpoint that her response was bcoz of only one or two of these reasons but bcoz a multitude of factors come into play when a person orgasms (especially if it's a woman) so yeah I'm gonna consider that it was probably all of these points that basically caused her to, as CC writes it, "you sounded almost surprised, as if you had not known or imagined what your body could give you."
Congratulations to you if you've reached to the end of my yapping, and thanks for this question, it was a lot of fun to answer! (I can't believe I just made a post explaining about Jocelyn's orgasm dynamics in detail of all things but yeah, this is all I have to say)