>>4463802 (lb)

"By this is meant the sucking of the blood from the wound. The mohel takes some wine in his mouth and applies his lips to the part involved in the operation, and exerts suction, after which he expels the mixture of wine and blood into a receptacle provided for the purpose. This procedure is repeated several times, and completes the operation, except as to the control of the bleeding and the dressing of the wound. "

Sauce: http://www.jewishencyclopedia.com/articles/4391-circumcision