That surprised noise she let out. That was all he needed to know he'd found another way to surprise her. Still he didn't think he'd be doing that too often. Maybe make it a sort of treat whenever she managed to work him up this badly. He could certainly embrace that slightly more beast like trait he could call upon.

"Mmmmm god you're just...you can drive me wild so easily Lucy~" Natsu growled out after managing to tear his lips away from her smooth skin for a moment.