Jami` at-Tirmidhi, Volume 1, Book 1, Hadith 136 (DarusSalam) ⓘ
Ibn Abbas narrated that : the Prophet said about a man who had sexual intercourse with his wife while she is menstruating: "He should give half a Dinar in charity."
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 " .
also referenced under: Hadith 136 (Reference) & Book 1, Hadith 136 (In-Book)