@moel Since chapter 9. Rotor is what she's always been called in the Japanese version. For whatever reason, the translator that started working on this series changed her name to Bullet, and while I'm trying not to be too inconsistent with previous translations, name changes for no discernible reasons is something I can't get behind, so I corrected it.
@Axalon The previous translators probably changed her name to Bullet so the joke behind her nickname would translate over more smoothly. See, the reason behind both nicknames is the character is constantly wearing a bullet vibrator in public, and my guess is Rotor is the slang for the thing over in Japan.
Outside of Italy you don't know De André, sadly, otherwise you'd all be singing:
"O la curiosità di una ragazza irriverente
Che li avvicina solo per un suo dubbio impertinente
Vuole scoprir se è vero quanto si dice intorno ai nani
Che siano I più forniti della virtù meno apparente
Fra tutte le virtù la più indecente"
Rotor vs bullet. Which translates to a vibrating dildo better.
Japanese porn and hentai sometimes calls vibrators "rotor", specifically those small egg ones.
I've never heard anyone call dildos "bullet" in porn, or anywhere for that matter, really.
Hence I vote Rotor.