Narrated by: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 .
Tirmizi
The Book on Purification • Hadith 136