He's had sex quite recently – within the last hour – but is somewhat more aroused and less sated than one might expect given that, though not much so in an absolute sense.
He seems to have a few additional types of organelles beyond those she's familiar with, present throughout his body but especially concentrated in the white matter, arcuate fasciculus, and right anterior insula, apparently exchanging energy and information with... either something that doesn't show up on her scan, or possibly with each other via some mechanism she can't perceive. There are also a few novel neurotransmitters, apparently produced by the conarium, which mostly but not exclusively interact with the unfamiliar organelles.
His feelings are, as is typical for a human, a complicated and ever-shifting cocktail.
When he looks at Cameron, he's less relaxed but has only marginally higher cortisol, and he has more of the various indicators of sexual arousal. Changes to his hormone balance include reduced lutropin and testosterone; and increased dopamine, orexin, serotonin, and vasopressin. Changes to brain activity include increased activity in the anterior cingulate cortex, ascending reticular activating system, dorsolateral prefrontal cortex, medial orbitofrontal cortex, thalamus, and ventral tegmentum.
When he looks at Tegan, he's more restful, and has more of the various indicators of sexual satisfaction. Changes to his hormone balance include more anxiolytic entactogens, lutropin, oxytocin, prolactin, and testosterone; and less norepinephrine. Changes to brain activity include increased activity in the descending reticular activating system, dorsal striatum, pars compacta, and tuberomammillary nucleus.
A third case, not obviously correlated with any particular outward sign, includes higher cortisol, mesocortical dopamine, norepinephrine, prolactin, and activity in the novel organelles; and lower endorphins, mesolimbic dopamine, and serotonin. Changes to brain activity include increased activity in the amygdala (but not the basolateral amygdala), hippocampus, locus coeruleus, mammillary body, precuneus, and thalamus; and decreased activity in the frontal eye fields, pontine tegmentum, and tectum.
He seems to sense her attention on him, and a pleasant frisson runs down his scalp and spine as he meets her gaze, arousal stirring.