What is really the butterlies in stomach feeling?

Hi EA. I would like to know what causes the butterflies in the stomach feeling and other symptoms that in the 3d world people asociate with feeling of "love"? I notice that happens sometimes with even random people that i am not even attracted to or some other random situations. There is also other sensations like body tingling  spcifically in the bottom spine so i was wandering is that a sudden kundalini boost and if yes, how come it gets triggered in seamingly random situations?