I've been putting Karryn through all sorts abuse but leveling spanking always gives me trouble, since everyone seems to prefer either groping her butt or fingering her anus and the desire thresholds are pretty tight.
Thugs are butt-slapping specialists and they also frequent the bar. Bar service is a good way to help Karryn discover the true purpose of having such a magnificent derriere. Apart from anal, of course.
Another way to trigger a barrage of spanks is giving up before thugs while keeping Karryn's butt desire high and other desires low low. Since they seem to never initiate penetrative sex, apparently content with rough-handling the Warden, they will slap her silly in no time at all. They're not really interested in butt groping or anal fingering, I noticed. Butt slaps mainly, then breast abuse and kisses / mouth fingering.
Every type of inmate has different kinks, so it helps to use these to your advantage.
Guards are the lewdest and quickest to penetrate.
Ordinary prisoners are too shy to initiate anything beyond a handjob. They will try groping, but nothing too rough (butt slaps / nipple pulling).
Goblins love groping and kissing in battles. They probably are good at cunnilingus, but since I am playing a pussy denial slut run, I haven't checked that yet. They're quite fierce butt fuckers at the Reception service though.
Rouges are into rimmings.
Nerds are into footjobs and toys. They can also last longer and cum twice in battle.
Slimes will penetrate as soon as a particular orifice desire requirements are met. They always cum twice and always cum inside. Perfect partners for Karryn to learn accepting spunk enemas and regain energy this way.
Ogres are boob-obsessed. Hobos are into anal. Lizards are stronger in groups, but I'm not sure if they have any sexual kinks.