Sunan Ibn Majah 650
سنن ابن ماجه#650Da'ifحَدَّثَنَا عَبْدُ اللَّهِ بْنُ الْجَرَّاحِ، حَدَّثَنَا أَبُو الأَحْوَصِ، عَنْ عَبْدِ الْكَرِيمِ، عَنْ مِقْسَمٍ، عَنِ ابْنِ عَبَّاسٍ، قَالَ كَانَ الرَّجُلُ إِذَا وَقَعَ عَلَى امْرَأَتِهِ وَهِيَ حَائِضٌ أَمَرَهُ النَّبِيُّ ـ صلى الله عليه وسلم ـ أَنْ يَتَصَدَّقَ بِنِصْفِ دِينَارٍ .
It was narrated that Ibn 'Abbas said:"If a man had intercourse with his wife while she was menstruating, the Prophet commanded him to 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:
Al-AlbaniDaif
Muhammad Fouad Abd al-BaqiDaif
Zubair Ali ZaiDaif
In-book reference: 1:384