ENOfficial
Ibn Abbas narrated that : the Prophet (ﷺ) said about a man who had sexual intercourse with his wife while she is menstruating: "He should give half a Dinar in charity."
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عَلِيُّ بْنُ حُجْرٍ، أَخْبَرَنَا شَرِيكٌ، عَنْ خُصَيْفٍ، عَنْ مِقْسَمٍ، عَنِ ابْنِ عَبَّاسٍ، عَنِ النَّبِيِّ صلى الله عليه وسلم فِي الرَّجُلِ يَقَعُ عَلَى امْرَأَتِهِ وَهِيَ حَائِضٌ قَالَ " يَتَصَدَّقُ بِنِصْفِ دِينَارٍ " .
sunnah.com