The sentence "I slept on Peter last night. It was chaotic" is grammatically correct, but its meaning is a bit unclear without additional context. It could suggest a few interpretations:
1. It might mean that the speaker literally fell asleep while lying on top of Peter, leading to a chaotic situation.
2. It could imply that the speaker spent the night at Peter's place, and the events or circumstances that occurred were chaotic.
To rephrase it