tactile hallucinations are common and the crystal did not cause it, rather it was just something for your mind to focus on.
im not discouting your experience even though it is placebo via crystal woo, rather this should give you an insight to the incredible power your mind has to influence your perceivable reality.
but please understand that beyond your experience, their is probably little practice application that can be derived from it, though i welcome you and would be thoroughly pleased to be proven wrong.
all said, enjoy it and next time, try to hold on and see where it takes you.