Hermione giggled, unable to stop herself. "You are really going to need to stop saying that or I am going to get a swelled head," she admonished Luna without any weight behind the words.
Seeing Luna's grin, Hermione knew that the younger Ravenclaw was enjoying the position she had put Hermione in. In truth, Hermione loved it too. She tried to keep her wits, with only partial success, as Luna began to bounce up and down in earnest.
Hermione's hands were on Luna's hips though she had no idea how they got there. Instinctively, she guided Luna up then back down again. The pace was quick and she urged Luna to go hard.
"Are you going to...come, Luna?" Hermione moaned. Watching in awe, she guided her to a fast and steady pace hoping Luna would come all over her as she rode her.