He should not include overly personal observations that might embarrass the couple and the listeners.
وَبُغْيَةَ إِظْهَارِ ٱلْإِكْرَامِ لَهُمَا ،‏ لَا يَجِبُ أَنْ يُرَكِّزَ عَلَى ٱلْمُزَاحِ أَوِ ٱلْمَفَاهِيمِ ٱلسَّائِدَةِ .‏