"It is the feast of S. Nichodemus of Thyatira, who was martyred by having goatskin nailed to his pate,"
'Christ talking with Nicodemus at night' (between 1616 and 1645)
Public Domain'Christ talking with Nicodemus at night' (between 1616 and 1645) - Credit: Crijn Hendricksz Volmarijn

It is not clear whether this is a joke or a serious reference.

There is a saint called Nicodemus, venerated by the Roman Catholic and Eastern Orthodox Churches, but there is no evidence to connect him with Thyatira (Akhisar in modern-day Turkey) or with any incident involving goatskin!

His feast day is August 3rd, which does not fit the reference in the text to the 'Easter vacation'.

Does anyone have more information about this?