>>5066537during adrenaline/dopamine surges your stomach also clenches in the same way (particularly when startled). your testicles will also naturally recede closer to your body when this happens and it activates the cremasteric reflex which causes the penis to shrink and retract a bit to avoid damage/provide more blood elsewhere
all this combined causes discomfort unless you really need to fight for your life, at which point it's beneficial and ignorable
i replied because i experience the same thing but have never heard anyone else mention it
