It means telling a horror story while eating very spicy food.
This kind of experience can make people feel two different emotions and stimuli at the same time. On the one hand, the spicy taste of food will make people feel hot and painful, on the other hand, the plot and content in the horror story will make people feel frightened, nervous and scared. The psychological explanation of this experience is that when faced with two different stimuli, people's brains will balance and coordinate these stimuli to avoid feeling excessive stimulation or discomfort.
when people tell horror stories while eating very spicy food, the brain will balance and coordinate the stimulation caused by spicy taste by increasing the attention and reaction to horror stories.