The custom of Upshernish, literally “to cut”, stems from the law that a Jew is not permitted to eat from a tree for the first three years, similarly there is a custom not to cut the hair of a boy till he reaches the age of three.
Rabbi Lazar could officiate at Upshernish ceremonies by explaining the significance of the custom and giving the young boy a Kippà and Tzizit that is customary to start wearing at the age of three.