From ShoujoMagic:

Miu Sakurai, age 15, attends a Catholic school where she prays every day for her admired Shion Amamiya to return her love. When that doesn't work, she places her faith in a book of magic and tries casting one of its spells. However, it's not love that manifests... it's Satan! "The recompense for the contract to grant your wish is your virginity," he tells her, and this is Miu's virgin crisis!

Vol. 4, Story 2: Satanic Honey
Malphas, who exists on Earth as Tsubasa, meets a young girl named Manami who has an unusual compassion for crows. She has two secrets which will transform Tsubasa's reasons for wanting to mature into a full demon...

Vol. 4, Story 3: Satanic Cohabitation
The continued adventures of Miu and Satan. Baal, who desires Satan's place as the Lord of Hell, kidnaps Miu to use as Satan-bait. But complications arise when Baal looks for the aspect of Miu that would attract a high-level demon... and finds it!