Sávuot / Táslumin

The Laws of "Nefilat Apayim" ("Falling on the Face"). Containing 8 S'ifim:
One should not speak between [the Amidah] Prayer and N'filat Apayim. When one "falls on one's face", the custom is to lean [on] one's left side [i.e. arm]. Gloss: And there are those who say that one should lean on one's right side [arm]. But the correct way (Rivash S'if 212; and Beit Yosef in the name of the Rokeach) is that during Shacharit when one has tefillin on one's left [arm], one should lean on one's right side [arm] because of honor for the tefillin. But [towards] the evening (i.e., when doing Nefilat Apayim during Mincha), or when one is not have tefillin on one's left, he should lean on one's left [arm]. (Minhagim [of the Maharil, etc.]) And after one "fell on his face", one should lift one's head and supplicate a little while sitting; each place should do according to their custom. And the widespread custom is to say "Va-anachnu lo neida..." ["And we do not know..."] and then Half Kaddish, Ashrei, and La-m'natzeyach (Tur). And even on days when we do not recite Tachanun, we say La-m'natzeyach, except for Rosh Chodesh, Chanuka, Purim, Erev Pesach, Erev Yom Kippur, and the 9th of Av. (Minhagim. And see below in siman 559)

The widespread custom is to not "fall on their faces" the entire month of Nissan, and not on the 9th of Av, and not between Yom Kippur and Sukkot. [And not from the beginning of Rosh Chodesh Sivan until after Shavuot.]

...

From Rosh Chodesh until after Shavuos. There are places that omit Tachnun for six days after Shavuot, because the sacrifices of Shavuos have seven days of Tashlumin - compensate.

The Gemara asks: Does everyone hold that one may recite the morning prayer only until noon and no later? Didn’t Rav Mari, son of Rav Huna, son of Rabbi Yirmeya bar Abba, say that Rabbi Yoḥanan said: One who erred and did not recite the evening prayer, prays in the morning prayer twoAmida prayers; one who erred and did not recite the morning prayer, prays in the afternoon prayer twoAmida prayers? Apparently, the morning prayer may be recited until the evening, at least in the event that he forgot to recite it in the morning.

On the topic of one who forgot to pray and seeks to compensate for the prayer that he missed, a dilemma was raised before them in the study hall: One who erred and did not recite the afternoon prayer, what is the ruling? May he recite in the evening prayer twoAmida prayers? The Gemara articulates the sides of the dilemma: If you say that one who erred and did not pray the evening prayer prays in the morning prayer twoAmida prayers, perhaps that is because the evening and the morning are both part of one day, as it is written: “And there was evening and there was morning, one day” (Genesis 1:5); the evening and the following morning constitute a single unit. But here, in the case under discussion, perhaps prayer is in place of sacrifice. Since in the case of sacrifice we say, since its day passed, its sacrifice is invalid and there is no way to compensate for the missed opportunity, the same should be true for prayer. Or, perhaps, since prayer is supplication, any time that one wishes, he may continue to pray?

One Who Did Not Pray Due To A Mistake, Or An Extenuating Circumstance, Or On Purpose. Containing 12 S'ifim
If one erred or was forced [by circumstance] and did not pray the morning prayer, one should pray the afternoon prayer twice: the first is the afternoon prayer, and the second as a make-up. If one inverted [the order], one has not fulfilled one obligation in prayer for the prayer which is a make-up, and one needs to go back and pray it [again]. And the same law applies in every case in which one must pray a make-up prayer.

...

It is prohibited to fast immediately after the holiday of Shavuot. Rem"a: And we do not say Tachanun from the beginning of Rosh Chodesh Sivan until the 8th day, which is after the post-holiday day (Hagahot Maimoni, Hil' Tefillah Umnagim). We have the custom to spread out plants on Shavuot in the synagogue and in houses, as a memory for the happiness of the receiving of the Torah. We have a custom everywhere to eat dairy food on the first day of Shavuot. And it seems to me that the reason is: It is like the two foods that are taken on the evening of Pesach, a reminder of the Korban Pesach and a reminder of the Korban Chagiga, so too we eat a dairy food followed by a meat food, and we bring with them two loaves on the table in place of the Mizbeach, and thus there will be a reminder of the two loaves that were brought on "The day of the Bikkurim."