[Seeking Help]

"Pretty sure it happened at least once!" Irena calls back as she descends the staircase.
To her credit, she is wearing sweat pants as opposed to only underwear. But no socks however, walking down in a pair of bunny slippers.
Eyeing Anastasia and then Eliseo, Irena gives them a flat expression. "I think your girlfriend is about to lose consciousness, all blood is going to her head." But suddenly she smiles. "Hey, don't worry about it you two. Eliseo can tell you I always pester him, and I make no exceptions. I just don't mean anything by it." She reaches out to ruffle Eliseo's hair. "So who're you anyway? Someone from school?"

[Northside - Fourth Tower Compound]

Zula raises her eyebrows in surprise. She had not expect him to blush of all things. "I see... ahem well, sinccubi have a great interest in such emotions so be cautious if you feel uncomfortable about it. They might use it to their advantage."

The books never really go into details on it, but there is a few mentions of "dream intercourse" in relation to their dealings with the sinccubi.