It is narrated from Sayyiduna Talq bin Ali (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When one of you wishes to fulfil his need with his wife, let him come to her, even if she is busy at the oven (baking bread)."
Hadith Referenceالمعجم الكبير للطبراني / باب الطاء / 8204