Yep - its a nervous reaction - not a laughing matter. When they are twitching its a knee jerk to get whatever it is to stop messing with them. Retics are known for doing this, especially when they do not want to be missed with. During feeding days if I need to clean the cage my Tigers will be slightly twitchy to warn me they are ready for food, so I always keep them out of reach to make sure I continue showing them respect. Remember, retics decide when its ok to handle them, watch for those signs.