POIS is vasodilation.

[FernandoPOIS]

Study a way to decrease your vasodilation.

Vasodilation happens for several reasons:

Low Testosterone
low dopamine
low serotonin
Inflammation/Allergy
Genetic predisposition to have low blood pressure.

Remember: After orgasm, dopamine drops, blood pressure drops, and everything gets worse.

If you want to be symptom-free, keep your body away from them.

Do physical activity.
Treat depression/ADHD
Correct your posture.
Treat your allergy.

At the time of crisis:
Analgesics to reduce the action of prostaglandins (vasodilator)
Antiallergic with pseudoephedrine (reduces histamine and causes vasoconstriction)
Plenty of water and electrolytes to keep blood pressure down.

I hope it helps.