There is a widespread custom to conduct Hakafot (literally, "encirclings") on Simhat Torah, both at night and by day, after Arbit and Shaharit. We walk around the Teba seven times, singing praises to Hashem, dancing and clapping in the Torah’s honor. During the Hakafot, a Sefer Torah is placed on the Teba, and the other Sifreh Torah are carried around the Teba. A God-fearing person should remain with the Sefer Torah on the Teba to ensure that nothing happens to it.
Despite the fact that clapping and dancing are generally forbidden on Yom Tob, and on Shabbat, it is nevertheless permissible to dance and clap on Simhat Torah to give honor to the Torah, even if Simhat Torah falls on Shabbat (which occasionally happens in Israel, where Shemini Aseret and Simhat Torah are celebrated together on the same day). In fact, not only did the Sages permit clapping and dancing on Simhat Torah, but it is considered a Misva to do so. The Kaf Ha’haim (Rav Yaakob Haim Sofer, Baghdad-Israel, 1870-1939) cites accounts of the Vilna Gaon (Rabbenu Eliyahu of Vilna, 1720-1797) fervently clapping and dancing on Simhat Torah, his eyes fiery like a torch as he celebrated in honor of the Torah. It is thus a Misva to sing, dance and clap with intensity during the Hakafot on Simhat Torah.
Of course, it is forbidden to play music on Yom Tob, even for the celebration of Simhat Torah. By the same token, one may not intentionally shake the Torah scroll so that the metal Rimonim will jingle, as this is forbidden on Yom Tob.
If a person lost a family member, Heaven forbid, during Hol Ha’mo’ed Sukkot, such that his mourning observance begins only after Simhat Torah, he may walk around the Teba during the Hakafot, but he may not dance and rejoice, due to his status as a mourner.
Summary: It is a Misva to sing, clap and dance during the Hakafot on Simhat Torah to give honor to the Torah. However, music may not be played, and one may not intentionally shake the Torah scroll to jingle the metal decorations. A person who lost a family member during Hol Ha’mo’ed may walk around the Teba during the Hakafot, but he may not dance and rejoice.
