שולחן ערוך אורח חיים · סימן תקנ״ה

English

The laws of tefillin and tzitzit on Tisha b'Av, contains 2 paragraphs: We are accustomed not to put on tefillin or a tallit on Tisha b'Av in the morning, but rather to put on a small tallit under clothes, and not make a blessing. And during mincha we put on tzitzit and tefillin and bless them.

English

There are those who are accustomed on the night of Tisha b'Av to sleep spread on the ground and to place a stone beneath their heads. Rema: and these are to pain a person regarding their lying down on Tisha b'Av; if a person is accustomed to lie with two pillows they will lie [on Tisha b'Av] with one. {Tosafot, end of Ta'anit} And there are those people who place a stone under their heads to remember what is said, "He took from one of the stones of that place" (Genesis 28:11) that had seen the destruction {Mordechai on Moed Katan}. Pregnant women, who are not able to cause themselves pain, are not obligated in any of this [Tosafot] And a person should decrease their honour and enjoyment on Tisha b'Av in all that is possible.]