I've done LSD and magic mushrooms a few times. In the bigger picture, psychedelics haven't done much to affect my stutter for better or worse; I think any long-term changes to my fluency from those trips are downstream effects of larger personal changes that came from psychedelic use. (I wouldn't say psychedelics have had a huge effect on my life, but I am happy I've had those experiences.) As for short-term effects, I've definitely felt my baseline fluency drop during an acid trip, and the morning after. From what little I know, part of the psychedelic effect is reducing your mind/brain's ability to put thoughts/experience into words. Psychedelics probably affect the linguistic areas of your brain, and stuttering and speech are heavily linguistic, so it makes sense that a psychedelic experience may temporarily exacerbate a stutter. If you're curious about psychedelics, keep researching. I don't think it will a major direct impact on your fluency either way, but you may find it personally meaningful. :)