Hadithcore
Mishkat al-Masabih, 409

‘Uthman said that the Prophet (ﷺ) used to make the water go through his beard. Tirmidhi and Darimi transmitted it.

وَعَنْ عُثْمَانَ رَضِيَ اللَّهُ عَنْهُ: أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ كَانَ يُخَلِّلُ لِحْيَتَهُ. رَوَاهُ التِّرْمِذِيّ والدارمي

References1 variant
In-Book Reference
Book 3, Hadith 114