Draco was unsure if Hermione was awake or not. However, he wasn't about to resist the urge to play with her arse if she encouraged him. Pushing against his finger was certainly encouragement.
With it nice and wet, his finger entered the tight rosebud easily. Gently and slowly, he began to work it in and out. Draco watched Hermione intently as his flaccid cock started to harden.