TLDR: Idea for Voodoo Fleshlight and lilith sharing her pleasure to make a character want mc dick desperately
Hey Breadman since you seem to be taking ideas I thought I would share mine, 2 originating from one idea, the first isn't specific to demon deals but I think it fits the setting well and I know you can turn it more hot than I originally imagined, and from what I heard brenda is very likely for the next update and I feel it could work with her disliking mc/ being more reluctant to fuck him.
Anyway idea 1 is a Voodoo fleshlight, that mc gets from Lilith as a reward or something. the important things about this is 1) mc has no clue it is magical, and what it's actually doing. 2) it is extremely durable and can take mc full length. 3) it not only feels as good as a real pussy but the harder he fucks it the better it feels, so mc is just going to town on this thing, so much that even this extremely durable magical item nearly gets broken by him every time he uses it. 4) and the final and whole point is that anything the fleshlisght "feels" gets transferred to a woman. Now for the woman she gets insane pleasure out of nowhere without knowing anything the first 1-2 times mc uses the item, then by the 3rd or 4th time she is looking forward to it, while for the 5th or 6th time she is desperate for the time of day when mc does his thing to come ( if it's leslie maybe she is rushing mc to go shower cause that's when it happens everyday), perhaps she doesn't know why its happening or maybe she has a hunch it has to do with mc. This would probably work best with leslie or any character that lives with mc, but for leslie like I said earlier she could rush mc through his chores so she's all alone for her orgasm time she's desperately waiting for, and it could be the final straw that pushes her over the edge making her fuck him. You could even do it where mc either breaks the fleshlight after his 6th time using it so he can't use it anymore or he becomes suspicious of leslie rushing him so he doesn't use it and goes to investigate, finding a dripping wet extremely sexually frustrated leslie who uses him to get off. Or with brenda after the 5th or 6th time she becomes visibly frustrated in class and her only cure is letting mc, who she dislikes, bend her over her desk and fuck her in the ass, maybe he catches her masturbating furiously but being unable to get off. You could even make it an item that can be used for a single scene with multiple women so long as mc collects something specific from them.
Idea 2 is more specific to Demon Deals but it shares the theme of pleasure sharing, in my opinion it would work best with the therapist (Sunny?), but it could work with any character that has a reason to watch mc fuck lilith, the character becomes so horny imagining what it feels like that she swears she can feel mc dick in her, and that's because she can feel mc dick in her cause lilith is sharing what she is feeling with her. This could also work as a final straw for leslie or someone else to let mc destroy their insides.
Anyways sorry for the essay but those were my ideas and I hope the release goes smoothly.