Suetonius, Life of Lucan
“When he was at the beginning of adolescence and learned that his father lived in the country because of a terrible marriage…Although when he was recalled from Athens by Nero he was included among his group of friends and even honored with a quaestorship, he still did not remain in his good graces.
Because he took it badly when Nero suddenly left while he was giving a reading for the sake of holding a senate meeting but for no other real reason accept for chilling the reading, he did not later on restrain himself from either words or deeds against the prince, some of which are well-known.
For instance, once when he was in the public restrooms, he followed a rather clear and loud fart to empty his bowels with a half-line written by Nero as the great crowd of those around him fled: “you could believe that it thundered beneath the earth.”
Hic initio adolescentiae, cum ob infestum matrimonium patrem suum ruri agere longissime cognovisset*** Revocatus Athenis a Nerone cohortique amicorum additus atque etiam quaestura honoratus, non tamen permansit in gratia. Siquidem aegre ferens, recitante se subito ac nulla nisi refrigerandi sui causa indicto senatu recessisse, neque verbis adversus principem neque factis exstantibus post haec temperavit, adeo ut quondam in latrinis publicis clariore cum strepitu ventris emissi hemistichium Neronis magna consessorum fuga pronuntiarit: Sub terris tonuisse putes.