Markandeyapurana 30.2-3

“The continual are comprised in the five sacrifices,[1] these that I have described to thee: and the occasional are the others, such as the ceremony on the birth of a son, and so forth. The periodical[2] are recognisable by the learned as the sacrifices at the moon’s changes, the śrāddha and others.

“Here[3] I will tell thee of the occasional śrāddha celebration, of the birth-ceremony that should be performed similarly by men on the birth of a son; and everything duly related in order that should be done at marriages and on other occasions. And in this the Nāndīmukha pitṛs[4] must be worshipped; and he should give the piṇḍas mixed with curds and containing barley, facing northward or eastward, with composed mind making the oblation. Some men like it with the offering to the Viśvadevas omitted. And in this ceremony the dvijas must he arranged in pairs, and must be worshipped in dextral circumambulation. This is the occasional ceremony during growth, and the other is the funeral obsequies.