Jami` at-Tirmidhi 136
جامع الترمذي#136Da'ifحَدَّثَنَا 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 " .
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
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Ahmad Muhammad ShakirDaif
Al-AlbaniDaif
Zubair Ali ZaiDaif
In-book reference: 1:136