It was a sinful act the two souls expressed in the maze of books.

Lavi and Circa had tested the privacy of the secluded corner in the library several times and it hadn't failed them yet. The redhead could lift the girl, press her back to the bookshelves, and give attention to the soft spot on her neck without worrying about unwanted eyes seeing them – especially the Bookman, but he thought Lavi was training. Circa still tried to prevent those acts from happening, but Lavi knew all the right moves to make her own lust control her actions.

"Lavi, I have to go soon," the blonde protest when she realized his hands were sliding up her thighs, but her head tilted to the right from his lips moving from her collarbone to ear.

"You still have plenty of time~" he countered, smiling at how she twisted between his body and the shelf from just him breathing in her ear. That little act was enough to get her to kiss him and pull his hair.

They always had a hunger for the other and it only made it harder for them to control themselves. It didn't matter if she bit his lip too hard because he'd just leave a mark on her neck each time she did. She didn't care that the bookshelf was uncomfortable – Lavi's hips grinding on her own made that pain fade away. The only thing – the thing that made them try to get closer to each other – that got in their way was their uniforms. It was a barrier they couldn't shed incase someone did wander by, so did what they could, like make the others lips bruise.

There would be days Lavi would sit there and wait to see if Circa was having the same thoughts as him and occasionally she did. Those where the days she would straddle him, his hands roamed her, and her tongue teased his lips. Still, they only did what they could get away with in a public place without being seen.

They knew lust was one of the seven deadly sins. They knew they were being unprofessional Exorcists by letting their emotions take over them. They knew they had to stop having these secret meetings. They knew that neither of their rooms would be able to contain what they wanted to release.

Maybe knowing it was a sin was what drove those two to want more.