The Messenger of Allah ﷺ one day made me mount behind him and he confided to me something secret which I would not disclose to anybody; and the Messenger of Allah ﷺ liked the concealment provided by a lofty place or cluster of dates (while answering the call of nature), Ibn Asma' said in his narration: It implied an enclosure of the date-trees.  

أَرْدَفَنِي رَسُولُ اللَّهِ ﷺ ذَاتَ يَوْمٍ خَلْفَهُ فَأَسَرَّ إِلَىَّ حَدِيثًا لاَ أُحَدِّثُ بِهِ أَحَدًا مِنَ النَّاسِ وَكَانَ أَحَبَّ مَا اسْتَتَرَ بِهِ رَسُولُ اللَّهِ ﷺ لِحَاجَتِهِ هَدَفٌ أَوْ حَائِشُ نَخْلٍ قَالَ ابْنُ أَسْمَاءَ فِي حَدِيثِهِ يَعْنِي حَائِطَ نَخْلٍ