The Messenger of Allah ﷺ happened to pass by two graves and said: They (their occupants) are being tormented, but they are not tormented for a grievous sin. One of them carried tales and the other did not keep himself safe from being defiled by urine. He then called for a fresh twig and split it into two parts, and planted them on each grave and then said: Perhaps, their punishment way be mitigated as long as these twigs remain fresh. (Using translation from Muslim 292a)   

مَرَّ رَسُولُ اللهِ ﷺ عَلَى قَبْرَيْنِ فَقَالَ إِنَّهُمَا يُعَذَّبَانِ وَمَا يُعَذَّبَانِ فِي كَبِيرٍ أَمَّا أَحَدُهُمَا فَكَانَ يَمْشِي بِالنَّمِيمَةِ وَأَمَّا الْآخَرُ فَكَانَ لَا يَسْتَنْزِهُ مِنْ بَوْلِهِ وَقَالَ وَكِيعٌ لَا يَتَوَقَّى قَالَ فَدَعَا بِعَسِيبٍ رَطْبٍ فَشَقَّهُ بِاثْنَيْنِ ثُمَّ غَرَسَ عَلَى هَذَا وَاحِدًا وَعَلَى هَذَا وَاحِدًا ثُمَّ قَالَ لَعَلَّهُ أَنْ يُخَفِّفَ عَنْهُمَا الْعَذَابَ مَا لَمْ يَيْبَسَا  

[Machine] I and Amr ibn al-Aas went out and the Messenger of Allah, ﷺ , came out with a container of water or something like it, and he sat down and covered himself with it. While he was sitting, he started urinating. So, I said to my companion, "Look at the Messenger of Allah, ﷺ , how he urinates like a woman while sitting?" So, the Messenger of Allah, ﷺ , came to us and said, "Do you not know what happened to the people of Bani Israel when one of them had some urine drops on him? He was struck with a punishment in his grave."  

انْطَلَقْتُ أَنَا وَعَمْرُو بْنُ الْعَاصِ فَخَرَجَ رَسُولُ اللهِ ﷺ وَمَعَهُ دَرَقَةٌ أَوْ شِبْهُ الدَّرَقَةِ فَجَلَسَ فَاسْتَتَرَ بِهَا فَبَالَ وَهُوَ جَالِسٌ فَقُلْتُ أَنَا وَصَاحِبِي انْظُرْ إِلَى رَسُولِ اللهِ ﷺ كَيْفَ يَبُولُ كَمَا تَبُولُ الْمَرْأَةُ وَهُوَ جَالِسٌ؟ فَأَتَانَا فَقَالَ أَمَا عَلِمْتُمْ مَا لَقِيَ صَاحِبُ بَنِي إِسْرَائِيلَ كَانَ إِذَا أَصَابَ أَحَدًا مِنْهُمْ شَيْءٌ مِنَ الْبَوْلِ قَرَضَهُ بِالْمِقْرَاضِ فَنَهَاهُمْ عَنْ ذَلِكَ فَعُذِّبَ فِي قَبْرِهِ