Bathing naked in a private, closed room

Answer

*وَلَا بَأْسَ أَنْ يَغْتَسِلَ الرَّجُلُ عُرْيَانًا فِي بَيْتٍ مُغْلَقٍ، وَالْأَفْضَلُ أَنْ يَسْتُرَ عَوْرَتَهُ* — "There is no harm in a man bathing naked in a closed place, but it is better that he covers his ʿawrah." (al-Fatawa al-Hindiyyah, 5/333)