Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
It is disliked to stand and urinate unless you have some excuse like an injury. It is forbidden to leave urine on the seat or to not clean yourself afterwards.
Answering your question, Sheikh Mustafa Umar, President of California Islamic University, states:
It is disliked to stand and urinate unless you have some excuse like an injury. It is forbidden to leave urine on the seat or to not clean yourself afterwards. It is also disliked to not seclude yourself when urinating as is done in most public urinals.
Aishah (may Allah be pleased with her) said, “Don’t believe anyone that tells you the Prophet (peace be upon him) used to stand while urinating. He always used to sit down.” (An-Nas’i, Ibn Majah, and Amad)
Prophet Muhammad said, “Allah detests it when two people relieve themselves uncovered and have a conversation.” (Abu Dawud and Ahmad)
Al-Mughirah ibn Shu`bah said, “I was travelling with the Prophet. When he needed to relieve himself, he went far away from me.” (At-Tirmidhi)
The Prophet said, “When you go to the restroom, take three stones with you to clean yourself. That will suffice.” (Abu Dawud)
Salman al-Farisiī was told, “Your Prophet has taught you everything, even how to use the bathroom.” He responded, “That’s right. He told us not to…use our right hand when cleaning and to not use less than three stones to clean ourselves after we finish.” (A-Tirmidhi)
Aishah, the Prophet’s wife, said to a group of women, “Tell your husbands to clean themselves with water because I am embarrassed to tell them. This is what the Prophet used to do regularly.” (At-Tirmidhi)
The Prophet passed by a man’s grave and told Ibn `Abbas that the dead man is being tortured, but not for a major sin: “He didn’t use to clean himself after urinating.” (Al-Bukhari)
The Prophet said, “Beware of the cursed ones.” Some people asked, “Who are the cursed ones?” He replied, “People who relieve themselves in public pathways or in shaded areas.” (Muslim)
Hudhayfah said, “The Prophet [while traveling] approached a garbage dump and stood while urinating. Then, he called me to bring some water for him, so I did, and he performed wudu.” (Al-Bukhari)
Almighty Allah knows best.
Source: AsktheScholars.com