Sayyiduna al-Mughirah bin Shu'bah (may Allah be pleased with him) narrated that the Messenger of Allah (peace and blessings be upon him) saw a man with a long moustache, so he called for a tooth-stick (miswak) and a blade; then he (peace and blessings be upon him) placed the tooth-stick under the moustache and trimmed it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 695