Siman 40

It is forbidden to hang tefillin, whether the battim are resting and the straps are hanging, or whether the straps are resting and the battim are hanging, for this is a disgrace when they are hanging in the air. This does not include when, during the donning of the shel rosh, one holds the strap and the shel rosh is hanging in the air and he places it on the head, for this is the necessity of their donning. And likewise during their removal when the straps are hanging, for such is also the manner of their removal. He should only see to it that the straps do not drag on the ground. And likewise, if by chance he holds the tefillin and the straps are hanging—we have no concern with it, for such is their way. But the opposite, to hold the straps and the tefillin are hanging—is forbidden even by chance (see Magen Avraham subsection 1). And likewise it is forbidden to hang them on a peg, whether the tefillin are resting on the peg and the straps are hanging, or whether the straps are resting and the tefillin are hanging. And thus they said in Berakhot (24a): One who hangs his tefillin—his life shall be hanging. Interpreters of verses said: "And your life shall hang in doubt before you"—this refers to one who hangs his tefillin. But if he placed them in a pouch and hung the pouch—it is permitted, for there is no disgrace here. Regarding a Sefer Torah, even in such a manner it is forbidden. And a Sefer Torah requires only resting in an Aron or in a chest (Gemara ibid.). And likewise, siddurim that are hanging by a silver chain—it is forbidden (Magen Avraham subsection 1). And this is when the chain is attached to the siddur, but to place it in a pouch and hang the pouch—it is permitted just as with tefillin (ibid.). And such is the law regarding other holy books.

A room in which there are tefillin—it is forbidden to engage in marital relations therein until he removes them or places them vessel within vessel. And this is provided that the second vessel is not designated for them, for if it is designated—even a hundred vessels are considered as one. And if he spread a cloth over them, even though the cloth is not spread from below—it is permitted (ibid. subsection 2). And the tallit is not called "their vessel." And those who always place the bag of the tefillin inside the bag of the tallit, the bag of the tallit is called "their vessel," and it is not effective. And he requires another vessel on top of it. And if both of them are not designated for them—it is obvious that it is permitted. And the same law applies if the inner one is not designated and the outer one is designated—it is also permitted. (That which the Magen Avraham wrote there regarding a mezuzah, we have already explained what appears to my humble opinion regarding a mezuzah in Yoreh Deah siman 286, see there.)

Even to place them in a vessel within a vessel—it is forbidden to place them under his feet, for this is a great disgrace to the tefillin. And likewise, it is forbidden to place them even at his head, and even in a vessel within a vessel if they are placed exactly opposite his head, for since his head is placed upon them—it is a disgrace, and even if his wife is not with him. Rather, he should place them at his head not opposite his head, and then if his wife is not with him—it is permitted even in one vessel (Taz and Magen Avraham subsection 3). And if his wife is with him—he requires a vessel within a vessel. And the pillow at his head is considered a vessel (ibid.). And know that "his wife is with him" means when he wishes to engage in marital relations. But otherwise, even if she is with him in bed, it is called "his wife is not with him." And to place them in the bed opposite his side—it is forbidden just like under his feet, for at his side it is also a disgrace to the tefillin. And there are those who wrote that to place the tallit upon the tefillin is a disgrace to the tefillin (Sha'arei Teshuvah subsection 4). However, this is only regarding their placement in the bag. But when he places the tallit for the purpose of a covering for the tefillin or in order to protect them—it is certainly permitted (ibid.). And there is a doubt whether the straps also require a vessel within a vessel or not. And the practical difference is, for example, if there is a case for the tefillin, and the straps are outside the case as is customary. Therefore, when he covers them with another vessel—it is a vessel within a vessel for the tefillin but not for the straps. And it appears that the primary concern is with the tefillin and not with the straps. Nevertheless, in practice one should deliberate, but according to the law it appears so. (See Taz subsection 4, who wrote that "his wife is with him" is the term even when he does not wish to engage in relations.)

And know that that which we wrote, that beneath his headrest is permitted when not directly opposite his head, this is all when they are guarded only in his bed because of mice. But when they are guarded in another place—it is not proper conduct to place them in his bed even at his headrest, unless it is in a place higher than his headrest by three tefachim or lower by three tefachim (Magen Avraham, subsection 4). For even to sit level with the tefillin on one bench is a disgrace, as I wrote in Yoreh Deah, siman 282. And when they place the tefillin in a chest in the synagogue, and the chest is the bench upon which they sit—there must also be a space of three tefachim from the opening of the chest above until the tefillin, or at least a space of a tefach. For if not so, it is as if he sits upon the tefillin (Sha'arei Teshuvah, subsection 5). And so too regarding siddurim and other books that are in the chest, it must be so. And thus they practiced, and one should not deviate.

If one forgot and engaged in marital relations while wearing tefillin – he should not grasp the strap, and certainly not the tefillin themselves, until he washes his hands. This is because the hands are active, and they certainly touched a place that requires washing of the hands. And when he washes his hands, he should remove them until he wipes away the semen, and afterwards it is permitted to wear them, for a ba'al keri is permitted in tefillin (Sukkah 26b). And if he slept in tefillin and saw a seminal emission – he should not grasp the battim. Rather, he should grasp the straps, and remove them until he wipes the semen from himself and washes his hands. Our teacher, the Beit Yosef, wrote in section 8: One who enters for a fixed meal – removes them and places them on the table until the time of the blessing (Birkat HaMazon), and then returns and dons them. But for a casual snack, he does not need to remove them. Thus far his words, for it is permitted to eat a casual snack in tefillin. And this is according to their custom when they walked all day in tefillin, but not for us. And it seems to me that for us, even a casual snack in tefillin is not proper.