That being said, mushrooms are not very good regardless so you can process them in a way that makes it palatable (teas, blended smoothies, etc). But that won't make that weird nausea feeling disappear, you just get used to it and it slowly becomes unnoticeable as you progress on the "experiment".
The nausea is a response of your body, telling you that you ingested something bad, because that basically what those things are: a poison, just a non-lethal one, and we know the positive fun effects so it makes it worth it, otherwise you would just want to throw up !
Last time I was sitting there miserable for an hour and I started thinking this is life in general. I can either continue to cry about the bad or try and fill my time with something positive. I started to take a walk and think more positively and it seemed to do the trick, for a bit anyway
also chewing fresh ginger or ginger tea
starting on an empty stomach, of course
but surprisingly, sometimes a little bit of miso soup midway can help with the "gastroparesis" type nausea that can emerge late stage
and also a little bit of diphenhydramine if it's still bad (like less than an antihistamine dose)
even if it is all kind of lipstick on a pig :)