Mishkat al-Masabih 3191
Ibn ‘Abbas said:
God’s Messenger received the revelation, “Your wives are a tilth to you, so come to your tilth . . .” (Al-Qur’an 2:223) that means from in front or behind, but avoid the anus and intercourse during menstruation. 

Tirmidhi and Ibn Majah transmitted it.
عَنِ ابْنِ عَبَّاسٍ قَالَ: أُوحِيَ إِلَى رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: (نساوكم حرث لكم فَأتوا حَرْثكُمْ)
الْآيَةَ: «أَقْبِلْ وَأَدْبِرْ وَاتَّقِ الدُّبُرَ وَالْحَيْضَةَ» . رَوَاهُ التِّرْمِذِيّ وَابْن مَاجَه