"Whoever tells you that the Messenger of Allah (ﷺ) urinated standing up, do not believe him, for he would not urinate except while squatting."
Sunan an-Nasa'i Book 1, Hadith 29
← Previous Hadith "And he wiped over his Khuffs," but Mansur did not mention the wiping.

Meaning, in this route, since Shu'bah narrated it from both Sulaiman and Mansur.

Sunan an-Nasa'i Book 1, Hadith 28 Next Hadith → "The Messenger of Allah (ﷺ) came out to us with a small leather shield in his hand. He put it down, then he sat behind it and urinated toward it. Some of the people said: 'Look, he is urinating like a woman.' He heard that and said: 'Do you not know what happened to the companion of the Children of Israel? If they got any urine on themselves they would clip that part of their garments off. Their companion told them not to do that and he was punished in his grave.'"

Sunan an-Nasa'i Book 1, Hadith 30