Musaf carries a second practice within it in many communities that is easy to overlook if the service is read only for its central petition about the sacrifices: the Priestly Blessing, Birkat Kohanim, in which men of priestly descent, Kohanim, bless the congregation using the biblical formula from the book of Numbers, a rite whose timing is bound tightly to Musaf in the diaspora tradition.
In Israel it is generally performed daily during the repetition of the morning Shacharit service, but outside Israel the widespread Ashkenazi custom restricts it to festival days, and specifically ties it to the Musaf repetition rather than to Shacharit, so that the blessing many communities experience as their only encounter with it in the year arrives embedded inside the very service whose sacrificial content already marks the day as distinct. The physical performance is itself distinctive and visually striking: the Kohanim remove their shoes, cover their heads and hands with a prayer shawl, and extend their hands with fingers parted in a specific configuration while reciting the blessing, a posture many worshippers are taught to avoid looking directly at during the recitation itself, out of a traditional caution that the moment carries a concentrated holiness.
Musaf on Yom Kippur additionally carries the Avodah service, a lengthy poetic reenactment of the high priest's Temple-era ritual on that single day of the year, which makes the Day of Atonement's Musaf both the longest single instance of the service and the one in which the sacrificial memory the prayer speaks about in the abstract is acted out in the most literal detail the liturgy attempts anywhere.