Sunan an-Nasa'i, Volume 1, Book 3, Hadith 370 (DarusSalam) ⓘ
It was narrated from Ibn 'Abbas from the Prophet concerning a man who has had intercourse with his wife while she was menstruating: "Let him give a Dinar or half a Dinar in charity."
أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا يَحْيَى، عَنْ شُعْبَةَ، قَالَ حَدَّثَنِي الْحَكَمُ، عَنْ عَبْدِ الْحَمِيدِ، عَنْ مِقْسَمٍ، عَنِ ابْنِ عَبَّاسٍ، عَنِ النَّبِيِّ صلى الله عليه وسلم فِي الرَّجُلِ يَأْتِي امْرَأَتَهُ وَهِيَ حَائِضٌ يَتَصَدَّقُ بِدِينَارٍ أَوْ بِنِصْفِ دِينَارٍ .
also referenced under: Hadith 370 (Reference) & Book 3, Hadith 22 (In-Book)