His partner may not be able to see anything, but Lan Wangji reaches out and strokes through his ponytail, then eventually rubs his shoulders and back in a soothing, relaxing manner. His touch and stroke are gentle.

He won't let anything happen to him while being on watch. For now, he is content staying with him while he relaxes and does his meditation. With Wei Wuxian drifting off, he doesn't wake up him, and eventually, he may have drifted off in a light trance during his meditation.