Originally Posted by ancman

23.I.11.e:

1) a single rotation of any length,
2) multiple rotations totaling no more consecutive days than the number of IVDs requested
3) no more consecutive reserve on-call days than the number of IVDs requested, or
4) a combination of rotations and reserve on-call days totaling no more consecutive days than the number of IVDs requested.

If you have two back to back 2-day trips, you could drop both with one IVD occasion, but it would require using 4 IVD days. You can’t use only 2 IVD days and drop both trips by touching only one day of each trip (unless you use more than one IVD occasion).