Quote Originally Posted by MFauli
Zenitsu didn't haven much appearance, but the one he did was fantastic. Both showing off to Nezuko AND awesomely saving people with his lightning move. However, it wasn't explained how he actually regained consciousness. The dream demon even mentioned at one point that Zenitsu hadn't woken up at all. Considering Zenitsu's technique relies on him falling asleep, it would have been interesting to see more closely how things went down here.
Zenitsu's body moves on its own, however his consciousness stops his technique from manifesting - so by putting him to sleep the demon basically enabled Zenitsu. His body just needs dire situations to drive his instinct to act.