sex_mechanics.rpy, though who knows what you'd have to edit in the mod since Trist has overrides in mod files. In the vanilla file, my edit begins at line 290. Here's the section I edited so you know what text to look for since it's unlikely to be the same lines in the mod, and what I edited in. It's a no-frills option to turn over control if she begs you to finish her off when you threaten to stop before she's cum even once. This is when she'd take over control if she were inclined, but at high obedience levels that stopped happening in the vanilla game. I don't know how or even if the mod has changes to that logic. It makes the same decisions she would if she took control herself, so if she's not slutty enough she might just decide she doesn't want to do anything after all and quit. Good luck hacking it in yourself
And to back up eldoen, I wasn't saying the mod changes anything for certain. I don't play the mod so I don't know if it has. I've just seen chatter that changes have been made to the taboo quests, so I was speculating that perhaps someone might have meddled. That's for you to confirm for yourself through play though. I was just trying to clear up what was possible in the vanilla game, namely to report that Vren did indeed write
specific dialog for when Jennifer breaks taboos herself during her wake-up event