Any psychedelic will be modified by other drugs you do while high. If you do speed, it's like pushing the ends of the trip's "curve" together...a spikier trip that doesn't last as long. Using downers tend to stretch it out, diminish the effect...if you do enough, you can terminate the trip. Since pot is both a psychedelic and a downer, the effects on acid tend to be a mellowing out...the psychedelic effect is a drop in the bucket. Although it sometimes help get off when you are taking weak acid or psilocybin or whatever. Thing is, mushrooms are a pretty mellow trip anyway...I have actually slept on them, as have others I know. So what you might experience is just making the high subtler and harder to identify...mellow it down towards not being as noticable or fun. One way to find out......