It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said concerning a man who had intercourse with his wife while she was menstruating: "He should give a dinar or half a dinar in charity."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12081