Keltham will be eating more of his food and wearing the fixed look of concentration of somebody trying to figure out which very standard dath ilani sex techniques in his very standard repertoire, that he did not expand much because he had other life priorities, would be able to cash in that "Surprises" promissory note. An obvious place to start would be to figure out which bits of standard technique would have no corollary inside a mess like Golarion, while still being executable by him... actually, that does narrow down a lot where to look? A vibrator would probably surprise her, but, of course, he doesn't have access to a vibrator. Okay, if he narrows it down from that angle, there's an obvious possible-surprise to try.
Keltham is also trying to figure out what Carissa could have possibly meant by 'hair-pulling'. If he just straightforwardly visualizes somebody pulling on his hair, it could be a moment of spontaneously passionate embrace, but mostly it would just yank his head back, and if it was hard enough to hurt, it would hurt? Though oddly enough, when Keltham tries to visualize the case where Carissa could have meant him pulling her hair - if she hadn't mentioned that in a sexual context, his unrevised first guess would be that it should just make her say ouch. But when he visualizes that producing a sexual response from her instead, that - seems to be booping on some internal sexual part of him that hasn't been booped before?
Yeah, he's probably going to lose this contest. That's what happens when you challenge somebody older and more experienced. It doesn't mean he's going to lose without dignity.
Keltham eats some more of his food, with the absorbed look of a horny teenaged male who knows he is in over his head and who is going to swim that fucking pool anyways.