Sunlight exposure causes nitric oxide release (which itself will have downstream effects on neurotransmitters). That's probably what you're feeling if I had to

Sunlight exposure causes nitric oxide release (which itself will have downstream effects on neurotransmitters). That's probably what you're feeling if I had to guess. FWIW the best way to get a feeling for what serotonin feels like is doing MDMA since it dumps massive amounts of serotonin out. It dumps plenty of dopamine too - it wouldn't be nearly as fun without that - but the unique "rolly" feeling is very attributable to serotonin. Not advising people take MDMA just to figure out what serotonin feels like, but for those who have it's very helpful to sort of "recognize" what different neurotransmitters feel like