The other night, he fought having lotion put on his back so I let him go to bed without it. He woke up SCREAMING. I went to get him and asked him if he had a nightmare. He said, "yes. I scared." and then made his scary hands and face. He slept in my bed that night.
The next night, he fought the lotion again. I told him that lotion would stop the nightmares and he immediately rolled over and let me put it on his back. Tonight, I got him to tell me (on camera) what happens when he has a nightmare.