Mughirah said, "I was a guest of the Prophet ﷺ one night, and he ordered that a side of meat be roasted. He took the knife and began carving pieces from it for me.Then Bilal came to call him to prayer. He set down the knife and said, 'What is the matter with him, may his hands be covered with dust!'"Mughirah continued, "My moustache had grown long, so the Messenger of Allah ﷺ trimmed it for me on a tooth-stick," or he said, "Let me trim it for you on a tooth-stick."
ضفت بالنبي ﷺ ذات ليلة، فأمر بجنب فشوي. قال: فأخذ الشفرة، فجعل يحز لي بها منه. قال: فجاءه بلال يؤذنه بالصلاة، فألقى الشفرة، وقال: ما له تربت يداه. قال مغيرة وكان شاربي وفى، فقصه لي رسول الله ﷺ على سواك، أو قال: أقصه لك على سواك.
Abu Dawud (188) and Ahmad (18212) both narrated it from the hadith of Waki, who said, Masaar narrated to us, from Abu Sakhra Jami bin Shaddad, from Mughira bin Abdullah, from Mughira bin Shuba, who said, and then he mentioned it. The wording is from Ahmad. Its chain of transmission is hasan because of Mughira bin Abdullah, whose hadith is hasan.