Well, it's not exactly hot chocolate. Not at all even. It's 100% cacao, which you can buy in these hard blocs. You then, in order to prepare the "medicine", you have to cut those hard bloc into pieces or shave off "cacao dust/powder" with a knife. It's actually a strenuous labour. It often comes from Peru, but you have it in India, Thailand, Mexico, etc. as well. Sometimes they heat the beans first so that the peel comes of, as the peel is considered to be useless or even to have adverse effects by some.
Physical sensation wise, I did feel expansion and warmth in my chest and heart area. I also felt a general aliveness and good feeling. I guess the active ingredient, theobromine, does that.
Theobromine is an alkaloid from the same family as caffeine, but it works slightly differently. The substance increases the heart rate, dilates the veins, and thus ensures faster blood circulation. This allows nutrients to be better absorbed and distributed throughout the body. This provides energy and mental focus.
The thing is, they call these events "Cacao Ceremonies". Some real shamans I know do not like this term, as they have no knowledge of (ancient) tribes or shamans using cacao for ceremonial purposes. Also, before you can call something a ceremony, there need to be certain conditions fulfilled. And there needs to be a capable leader. Cacao doesn't give you hallucinations or a glimpse into other realms or your own imagination as plant medicines do.
What they do in these cacao ceremonies is gather in a circle, doing an opening circle where everyone says their name and intention, they pass around the cups an encourage everyone to look into the eyes when they let every cup pass through all the hands clock-wise, sometimes people even "add their love an light" into the cups which they pass.Then there often is music or dancing and sometimes there are relational exercises (eye gazing, consensual touch, etc.), then there is a closing circle where the participants can share their experience in one word.
So, a lot of good feelings because of the theobromine but it's also quite the sherade once one has knowledge. Although, I wonder, if these people who attend are there in the full belief that sending love and light is good, are they then not asking (whether it be consciously or unconsciously) to receive that love energy from, in this case, the other participants sending their love into the cups they will drink. And if it is understood and agreed upon by everyone that this will happen and they consent with it, could it be that love is being given freely to those who sincerily ask?
I guess there are some nuances but maybe I'm off and it's just a kind of play and delusion and they only feel good because of the substance.