Q. Re- question #1074, that Rashbi and his son when hiding in the cave put on their clothing for saying shema according to Tosafot. Is that correct?, I remember learning that reading shema is the same as saying a bracha and unlike tefila, as long as your private parts are covered, there is a hefsek between them and your heart and your head is covered too, you can read shema?
Did Rashbi cover himself completely with sand when learning Torah?

A. Shulchan Aruch (O.H. 74: 6) rules that for the sake of reciting the shema it suffices if one covers downwards from his loins. Therefore indeed a swimsuit fulfils the requirement and since it is tight at the waist it also separates the rest of the body. However, for the purpose of reciting the amida, since one should be seen as standing in front of the King and speaking to Him, he requires proper attire. (ibid. and Mishna Berura 24)
Horav Shlomo Miller’s Shlit’a opinion is that Rabbi Shimon Bar Yochai because of his outstanding spiritual greatness and the exalted heights of his kedusha, would cover himself totally with sand when learning Torah and even for krias shema would use the proper attire normally required for tefila. (See similar opinion in Avodas Masso p. 17) The above constitutes a most remarkable and unparalleled feat of “amelus” in Torah and learning “mitoch yisurim”; learning Torah while being totally buried in sand continuously for thirteen years.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a