Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) said: The Prophet (peace and blessings be upon him) passed by me while I was skinning a sheep, and he (peace and blessings be upon him) said to me: "O Mu'adh, give it here - or: show me -" Then he (peace and blessings be upon him) pushed (his hand) between the meat and the skin twice, then said: "O Mu'adh, do it like this." Then he (peace and blessings be upon him) went on to the prayer.
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17268