"Pillow Talk"
Enjolras talks in his sleep all the time, mumbling and grumbling about all kinds of utter nonsense, and occasionally letting stuff slip that he'd never admit to otherwise.
Eponine is more than happy to play along, teasing and dropping hints about these revelations during the daytime as she potters around the apartment, desperately trying to hide her smirk from his wide eyed stare.
(He can never quite work out how she's so insightful).