There's quite a bit of stuff you could do wit that then... The sit animation could go from normal, to knees together with ankles apart, then to ankles together with knees apart. The walk could change, The idle could change. You could do away with any kind of heads up "meter" all together. Just go off visual ques.
Maybe give different followers / player characters "personalities". Like one gets a combat buff when aroused, and arousal goes up when they are in combat. So you have this huge combat buff... but then you would need a downside. Maybe you can't bring up the perk point screen to allocate perks unless you get your arousal to 0 or something. Then it takes a long time to recover. (also when you have max combat buff, you should not be able to ride a horse, because blue balls.) Another one might be just the opposite. One might absolutely hate getting cucked. Another might love it.
Maybe one could get aroused from using illusion magic (like they like the idea of controlling people) but that same person loses skill in illusion and sneak if they get too aroused because they can't focus.
Could also modify arousal gains/losses based on https://www.nexusmods.com/skyrimspecialedition/mods/13068/?