Ask if she wants to go somewhere more private.

'So..., do you fancy going somewhere a bit more private?'

Hermione looks at you. At first the expression on her face is confusion, then she catches on to what you're suggesting. An smirk crosses her face and she puts down her quill on the desk.

'You want to go somewhere private do you?' She asks, though you're pretty sure she's already made up her mind and is just playing along, and what Mr Doe would we do in private that we can't do here.

She's pressing her body a lot closer to yours now. Your cock is at breaking point. She looks down to see the strain in your trousers and her eyes light up.

'Well well well, what do we have here.' She makes a move to touch it but pulls back, the smirk growing all the time.

'I know you're game. Think you can just trick me into falling into bed with you. How pathetic... well here's my answer.'

She presses down on your leg and leans forward to whisper into your ear.

'I think we should.'

She grabs your hand and pulls you out of the library, your books forgotten. You honestly didn't think it would be that easy. But maybe Hermione is fed up with Ron. Maybe she wants something a bit different. For now though, you don't mind as you let her lead, but you're not exactly sure where she's taking you.