Ali narrated from Al-Husayn ibn Abi Al-Ala. He said:
I asked Abu Abdullah عليه السلام about madhy (pre-seminal fluid) that touches clothing and sticks to it. Imam عليه السلام said: "He should wash it, but he does not need to perform wudu."
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 1, p. 269