Answer: Posture is optional at this time of the Mass. Section 43 of the General Instruction on the Roman Missal (GIRM) states: “they may sit or kneel while the period of sacred silence after Communion is observed.” Keep in mind that this time is to be spent in private prayer. “When the distribution of Communion is finished, as circumstances suggest, the priest and faithful spend some time praying privately” (GIRM §88).