I was just thinking, channelling's effectiveness drops off rapidly at higher levels, and Sanguine is a max level vampire. With her turn resistance on top of that, most of his options involve potentially lethal results, which is why he'd have a hard time repelling her. Lay On Hands becomes something like inflict critical wounds at his level, and his other options involve divine fire, or stabbing her with a magic weapon. Unless he's going to wrestle her to the ground and sit on her until she calms down. And like he pointed out, she's got a ridiculous number of caster levels. She could probably cast spells by accident if she took all those easier casting feats or whatever. She's already demonstrated an ability to cast spells without saying anything, and potentially without gestures. If he sits on her, and her angry self starts conjuring angry undead or something, she's going to get caught in the backblast of him dealing with them. 

And it's not just a matter of stopping her, he wants to do so without injuring her to maximise the potential for sexy times.