After reading your post and some ayahuasca info about shamans/icaros, I decided to try it.
4 of us were in my dark living room, we played rainforest sounds in the background, with a 3-4 minute icaro at the beginning.
We started them both at the same time each person started to toke (we each went after each other).
I can't actually say how the Icaro effected me, just that this DMT trip was crazy intense. After blast off it was all black, I could only see the DMT manifested in beautiful colored patterns, I could see from the molecules point of view, flowing down my throat as a tangible pattern of color, it took up all the space in my throat and I felt a struggle to get oxygen.
After that I wasn't me, I wasn't anything, I was everything. But as I started being put back into body and ego I could see the patterns flowing into everything around me. But I suppose it was actually the patterns leaving. I have no idea why, maybe I exhaled and saw an effect...but I started manipulating the patterns.
Depending on how heavy, loud, etc my exhalings were, I could control the colors and patterns to a certain degree, then I started hovering my hand and moving it above my torso up and down, which seemed to help.
I did this for a while, but then it all faded and I came back, and when asked to explain wtf just happened, I could only giggle, until further reflection.
I want to meet a real ayahuasquero and do this the real way, but until then...I'm going to keep experimenting with Icaros.
Oh btw, the one played was a "Spiritual Protection" song.