الْقِيَامُ إِلَى السُّنَّةِ مُتَّصِلًا بِالْفَرْضِ مَسْنُونٌ
When a regular Sunnah prayer follows the Fard, the preferred pattern is not to turn the interval into a long sitting. The commentary explains that a short pause for the transmitted formula such as اللَّهُمَّ أَنْتَ السَّلَامُ وَمِنْكَ السَّلَامُ... is sufficient before standing for the Sunnah.
Other post-prayer litanies may be read between Fard and Sunnah according to one reported view, but the commentary says it is preferable to delay the longer set of remembrances until after the Sunnah. Long worldly conversation, eating or drinking does not invalidate the Sunnah, but it reduces the intended continuity and reward.