Summon D for Demon by Dove Soleil

The book said “Pleasure.” This is apparently what the universe thinks I mean by that. Silvia didn’t expect the spell she found in the old hall closet grimoire to work at all, let alone summon a demon. She certainly didn’t expect to summon only one… very specific and enormous part of him. But what starts as loneliness quickly turns to connection. She brought him here by accident, but she brought him back on purpose. Each time, there’s more of him, no matter how much he tries to hide. Ari isn’t ready to be seen yet, but he’s falling for her just as hard as she’s falling for him.