הלכה על מכות 3:12

From the laws of the commandment is that which they, may their memory be blessed, said in the chapter mentioned (Mishnah Makkot 3:12-14), "How do they lash him? His two hands are bound on each side of the column and the administrator grabs his clothes. If they are torn, they are torn (so be it), and if they become unstitched, they become unstitched, until his heart (chest) is uncovered. And a stone is placed behind him and the administrator stands on it. And a strap of calfskin is in his hand, doubled over once into two [straps] and a second time into four [straps] and there are two [other] straps going up and down with it. The [strap's] handle is a hand-breadth [long] and [the strap] is a hand-breadth wide and its tip reaches to the mouth (beginning) of his stomach. And he lashes him one third [of the lashes] on his front and two thirds on his back [...] The reader would read, 'If you do not guard to do [...] And the Lord will increase your beatings, etc.' (Deuteronomy 28:58-59)." And the rest of its details are elucidated in the mentioned chapter of Tractate Makkot (see Mishneh Torah, The Sanhedrin and the Penalties within their Jurisdiction 6)