After the initial excitement quietens down, Hermione finds herself catching up with Neville when she feels a tickling buzz from within her silk panties. Trying to stay focussed on what Neville is telling her, she looks around the room to see Draco in a deep conversation with Harry. She wondered how he was doing it, his charm work was exemplary. When the light tickle increases to a warming hum, she has to force herself to focus on her conversation.