DB webcomic CH6 page 67 (Patreon)

Wolfenstahl:

Yeah Ferania is basically 'microwaving' him.

Of course the microwave hasn't been invented yet, technically.

So she doesn't know that term.

Also, observant readers may notice that this encounter builds on their first fight from chapter 1 ^^

Crescentia:

Sound like Ferania figured that out by trying to heat up food on a camping trip.