Well, if nightmare was good, she go excessive force SM mode on his lewd dream. Which should turn it straight back to nightmare. Unless he is a hardcore SM simp, which he isn't because when he got railed, he cried in pain, not pleasure.
Looks like Nightmare-chan is in a predicament and likely being used by someone. Her face at the last page confirmed it more or less. Also, I feel like Nightmare-chan has the hots for MC.
P.S. That girl must have a better cleavages than Haruka.