Bhashya
स यां स्वभार्यामिच्छेत्- इयं मां कामयेतेति, तस्याम् अर्थं प्रजननेन्द्रियम् निष्ठाय निक्षिप्य, मुखेन मुखं संधाय, उपस्थमस्या अभिमृश्य, जपेदिमं मन्त्रम्- 'अङ्गादङ्गात्' इति ॥
In plain words
If it is his own wife he wants to love him, he enters her — his organ of generation placed within her — mouth pressed to mouth, touching her secret place, and murmurs this same mantra: 'From every limb...'
Close to the Sanskrit
If he should desire his own wife — [wishing] 'let this woman love me' — having placed, that is inserted, his organ of generation within her, having joined mouth to mouth, and having touched her private part, he should murmur this mantra: 'From every limb...'