Yup had this a few times..once I took probly like 4 grams of cubes and began to trip incredibly hard..one of the deepest trips I can remember..Near the end of the experience I had a muscle spasm in my neck and sort of along my jaw and it really freake me out..but I had had it a few times before with mushrooms and DMT in my leg etc..it lasted probly 3-4 minutes and was painful..it really hurt to swallow and talk..suddenly it just let go and I was okay.
Hydration might be an issue I cant say. I have not had it happen since that time about 8 months ago, but for a while after I was really freaked out when I took mushrooms over the thought of it happening again. I think actaully that it has to do with clenching the body when tripping..it seems I was doing it every time that it has happened. Riding a bike is something I can imagine brining it on.
Who knows really..I remember Stamets saying he thinks psilocin is a nerve tonic..
Long live the unwoke.