cocaine mixes awesomely with psychedelics, but only when used appropriately.
I like to use it for the come down/ transitional period of the trip.
Sometimes I have been involved in some pretty hectic parties.... like, parties where after a sheet or vial (divided between the patrons) the dope man shows up to the party around 4 in the morning with literally a few OUNCES of blow to sell.
I swear the dealers and the people who lived in the house were in things together. Because i swear every weekend there would be huge parties at their house, not just big parties, but huge, GOOD parties. And it would never fail that 4 am shows up, we are all out of drugs, here come the late night dealers, always showing up in a group of 3, and with all the expensive egoistic drugs we could possibly desire to do....
Needless to say, they would show up to the party for 30 minutes between 4am and 5 am and leave with thousands of dollars.
But seriously, cocaine and psychedelics are like yin and yang or whatever. And I dont even DO cocaine very often, but when I do cocaine, I DO cocaine.
I would save it for the end of the trip though, when its at the point where the trip is "over" unless you force yourself to keep participting.... once you get to that point start the blow or coca, then you can get another few hours out of your mystical experience.