ENOfficial
It was narrated that Ibn 'Abbas said: "If a man had intercourse with his wife while she was menstruating, the Prophet (ﷺ) commanded him to give half a Dinar in charity."
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ الْجَرَّاحِ، حَدَّثَنَا أَبُو الأَحْوَصِ، عَنْ عَبْدِ الْكَرِيمِ، عَنْ مِقْسَمٍ، عَنِ ابْنِ عَبَّاسٍ، قَالَ كَانَ الرَّجُلُ إِذَا وَقَعَ عَلَى امْرَأَتِهِ وَهِيَ حَائِضٌ أَمَرَهُ النَّبِيُّ ـ صلى الله عليه وسلم ـ أَنْ يَتَصَدَّقَ بِنِصْفِ دِينَارٍ .
sunnah.com