´It was narrated from Ibn 'Abbas that:` The Prophet said concerning one who has intercourse with a woman when she is menstruating: "Let him give a Dinar or half a Dinar in charity."
Hadith Referenceسنن ابن ماجه / أبواب التيمم / 640
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:ضعيف, إسناده ضعيف, سنن أبي داود (264), انوار الصحيفه، صفحه نمبر 401