Charles Ellicott Commentary Leviticus 23:20

"And the priest shall wave them with the bread of the first-fruits for a wave-offering before Jehovah, with the two lambs: they shall be holy to Jehovah for the priest." — Leviticus 23:20 (ASV)

And the priest shall wave them ... with the two lambs. — During the Second Temple, this was done in the following manner: The two lambs were brought into the Temple and waved together or separately by the priest while still alive. After this, they were slain, and the priest took the breast and shoulder of each one , laid them down beside the two loaves, put both his hands under them, and waved them all together or separately towards the east, forwards and backwards, up and down.

He then burned the fat of the two lambs, after which the remainder of the flesh, which became the portion of the officiating priest, was eaten by him and his fellow priests. Of the two loaves, the high priest took one, and the other was divided among the officiating priests, who had to eat them within the same day and half the following night, just as the flesh of the most holy things.

After these prescribed sacrifices had been offered, each individual brought his freewill offering. This offering formed the cheerful and hospitable meal of the family, to which the Levite, the widow, the orphan, the poor, and the stranger were invited.