Does he still not trust us?
Would it be a surprise if he didn't? That's kind of the point of the random scenes you can get with him in Hawkethorne I thought. I mean its true that the Champ did him a real solid during the recruitment scene but you're still total strangers. It'd be more weird for him to start spilling all his secrets and trusting you unconditionally rather than slowing warming up to the Champ and getting to know them.
Think about it from his perspective; This group of people hell bent on destroying your cult finds you and randomly decide to be somewhat nice to you. They help you out a bit but most of them openly don't like you and attempt to harass you into leaving one of the only safe places from the corruption almost every day. Are they helping you because they're actually good people or are they just keeping you around until you spill all your secrets so they can toss you away or kill you once you've outlived your usefulness? Its not as simple as just saying you're all on the same side now and lowering every single emotional barrier you have to someone you just met a week ago. While I'm not fond of using the "realism!" argument personally I can say that it does feel more believable for Quin's character to not instantly warm up to the Champion and their party.
Now is it okay for Quin to be walking around dosing people up without their consent on the magical equivalent of MDMA? Totally not okay at all, not even as a "lol your horny now" prank. You are forcefully altering the chemistry of another living being so it does what you want it to do and at that rate you may as well just straight up drug them. It'd be different if it was just physical teasing or sultry looks from across the room to try and get your attention but its not. Do I think Quin would honestly take advantage of someone with his magic given the chance? Yeah he probably would, and while that is definitely a bad thing I'd argue its much better than going out like the cult is doing and actually beating people into submission before raping them. So little steps I guess? We should also keep in mind that the culture regarding sex and loss in combat is fundamentally different than what we're use to in the real world.
However I still think those character flaws are what makes Quin a good companion. He's not some righteous hero trying to save the world because of some noble goal or anything, he's an average person like us. Socially tolerated at best in most groups, not a terrible person at heart but most people assume the worst anyways, has some bad habits that should be corrected but would willingly change over time for the right people, has trust issues but wants to be accepted at the same time. Maybe some of that is my own personal bias towards the character but who knows. Regardless, I feel confident in saying that if everyone here had the same abilities as Quin we'd probably take advantage of it in a similar way as him. I don't mean that as an insult either, we're all a bunch of weirdo perverts by the standards of normal society. As long as we're able to acknowledge that this sort of behavior isn't acceptable in real life we can keep those sort of fantasies contained in media like CoC without lines getting blurred. That's my thoughts on the matter.
EDIT: I also just wanna say that I did NOT expect these kind of thought provoking conversations on the forums, not gonna lie. Ya'll are awesome.