I started practising SFQ level 1 exercises just over a week ago. I know that the manual said that itchiness may be an initial side effect but I woke up the other night with a vibration running from my mattress through my feet. It felt a little like feeling a vibrating mobile through the mattress and it was intermittent too. I couldn't find any reason for this and it wasn't unpleasant but a little annoying. I'm not even sure if it has anything to do with SFQ but I wonder if anyone else has experienced this sort of sensation. Thanks