He got all that energy from the spot where a belly button would be on human. Since he was laying on Alison and that spot was pressed against her, all that energy was seeping into his system. Also, cannoli filling was heading his way.

"Any time. As much as I want. Wherever I want in a big, empty castle." He nodded. Then he looked around for the box of chocolate. Ah ha! He snagged it and dragged it over.