One should never see the Sun at the moment of rising, nor should one gaze at a naked woman who is another man's wife. Living with one's wife (in her season) is not sinful, but it is an act that should always be done secretly.
नेक्षेतादित्यमुद्यन्तं न च नग्नां परस्त्रियम्। मैथुनं सततं धर्म्यं गुह्ये चैव समाचरेत्॥