my vyvanse gave me this, and my dr didn't even believe me. As a former mental health therapist, i knew that i wasn't imaging this.  I did some research and I found out what some others have mentioned, however I also tried the suggested oral rinse Botene.  You can get generic at half the price at Walmart. You only use 1 tablespoon several times a day. Swish it around the mouth for about 30 seconds and spit out. You don't swallow it.  Wow!! what an immediate difference!!   Beware, this dryness of the mouth can cause tooth decay.  Your saliva helps with bacterial overgrowth in your mouth and with this gone, your bacteria grow faster. Also, drinking acidic drinks will make this worse. That eats your enamel.  This should be told to EVERYONE on stimulants.  Brushing often and rinsing the mouth after eating will help.  I was able to get relief within a couple of hours. No burning tongue and no constant movement. I believe the constant movement is your body doing pretty much what it normally does, BUT you are awre of it, because your saliva usually coats your teeth and your tongue GLIDES over them without noticing.  When your mouth is dry, you have the cracks, and crevices of your teeth much more apparent and you beocme aware of it more easily.  Your tongue may be trying to "bathe" your mouth with saliva that isn't there. 

The oral rinse was HUGELY beneficial...and I am much more watchful about brushing each day lightly a few times a day....oh, when I use the rinse, it lasts about 5 hours, if you aren't eating during that time.  You can actually feel it going away when its time again.  Also, parched lips or if you are using a lot of lip balm, its a sign as well....The sympathetic nervous system is activated, which stops the salivation...Hope this helps..