sashh I don't know where you got your information on religious circumcision being done with a fingernail. The suction of blood is done via a tube - there is no mouth to penis contact for hygeine reasons, except in very closed religious circles who shun the modern world - I'm not talking about ultra orthodox in general, I mean very small, insular groups. Orthodox society generally shuns this as unhygenic and uneccessary due to modern techniques/equipment.
More from www.jewfaq.org on the whys and hows of Jewish circumcision:-
The commandment to circumcise is given at Gen. 17:10-14 and Lev. 12:3. The covenant was originally made with Abraham. It is the first commandment specific to the Jews.
Like so many Jewish commandments, the brit milah is commonly perceived to be a hygienic measure; however the biblical text states the reason for this commandment quite clearly: circumcision is an outward physical sign of the eternal covenant between G-d and the Jewish people. It is also a sign that the Jewish people will be perpetuated through the circumcised man. The health benefits of this practice are merely incidental. It is worth noting, however, that circumcised males have a lower risk of certain cancers, and the sexual partners of circumcised males also have a lower risk of certain cancers.
The commandment is binding upon both the father of the child and the child himself. If a father does not have his son circumcised, the son is obligated to have himself circumcised as soon as he becomes an adult. A person who is uncircumcised suffers the penalty of kareit, spiritual excision; in other words, regardless of how good a Jew he is in all other ways, a man has no place in the World to Come if he is uncircumcised.
Circumcision is performed on the eighth day of the child's life, during the day. The day the child is born counts as the first day, thus if the child is born on a Wednesday, he is circumcised on the following Wednesday. Keep in mind that Jewish days begin at sunset, so if the child is born on a Wednesday evening, he is circumcised the following Thursday. Circumcisions are performed on Shabbat (the sabbath), even though they involve the drawing of blood which is ordinarily forbidden on Shabbat. The Bible does not specify a reason for the choice of the eighth day; however, modern medicine has revealed that an infant's blood clotting mechanism stabilizes on the eighth day after birth. As with almost any commandment, circumcision can be postponed for health reasons. Jewish law provides that where the child's health is at issue, circumcision must wait until seven days after a doctor declares the child healthy enough to undergo the procedure.
Circumcision involves surgically removing the foreskin of the penis. The circumcision is performed by a mohel (lit. circumciser; rhymes with oil), a pious, observant Jew educated in the relevant Jewish law and in surgical techniques. Circumcision performed by a regular physician does not qualify as a valid brit milah, regardless of whether a rabbi says a blessing over it, because the removal of the foreskin is itself a religious ritual that must be performed by someone religiously qualified.
If the child is born without a foreskin (it happens occasionally), or if the child was previously circumcised without the appropriate religious intent or in a manner that rendered the circumcision religiously invalid, a symbolic circumcision may be performed by taking a pinprick of blood from the tip of the penis. This is referred to as hatafat dam brit.
While the circumcision is performed, the child is held by a person called a sandek. In English, this is often referred to as a godfather. It is an honor to be a sandek for a bris. The sandek is usually a grandparent or the family rabbi. Traditionally, a chair (often an ornate one) is set aside for Elijah, who is said to preside over all circumcisions. Various blessings are recited, including one over wine, and a drop of wine is placed in the child's mouth. The child is then given a formal Hebrew name.