The cut-off refers to a specified date in the Senate sittings. It is marked on the Senate sitting calendar by a pair of scissors. Debate on bills received from the House of Representatives or introduced by a Senate minister after the cut-off are automatically adjourned until a set date. Standing order 111 provides the basis for the calculation and the postponement date.
With the agreement of a majority of the Senate, a bill or package of bills can be exempted from the cut-off, allowing it to be introduced, considered and passed in the same period of sittings.
Brief Guide to Senate Procedure No. 16- Consideration of Legislation
Senate Brief No. 8- The Senate and Legislation
Senate Standing Order 111
Odgers' Australian Senate Practice - Chapter 12