It isn't the first time and won't be the last. As Natsu doubled his efforts, Lucy squealed, breaking into a fit of giggles, "Her-Herb, Help!" She protests, laughing.

Poor Herb, he didn't know what was going on, but he wanted to get in on the fun! By standing and barking. You humans are being silly~!

Laughing as much as she was, though, she couldn't hold out against him for long, especially since she couldn't really defend herself. "Ahahaahaha~~! O.. Okay! okay! I give!~ The spellword is .. um..aa..ahah.. Starlight~!"

Obviously it would be star themed.