520. Distributing the Bread
Brachos 7:5
The one who breaks bread should give a piece to each person, who picks it up with his hand. The one distributing it should not put the bread directly in the hand of the recipients except in the case of a mourner. The one breaking bread should take and eat some bread first; the others may not eat until he tastes the bread. The one who recited the bracha may not taste the bread until the others have finished replying amen. If the one who broke bread wants to honor his teacher or a scholar of greater standing by allowing him to take bread first, he may do so.
Brachos 7:6
Two people eating from the same dish should wait for one another; three people need not wait. When two have finished eating, the third should stop; when one finishes eating, the other two need not stop. One should not talk during a meal for safety reasons (i.e., potential choking). For this reason, if wine is brought in the course of the meal, each person should recite his own bracha. If one were to recite the bracha and another to answer amen while in the act of swallowing, it could be dangerous. One should not stare at a person who is eating, or at his portion, because this could embarrass a person.