The defense pulls the disc to the offense
With the initial set up, we WANT them to throw the disc to the sideline, as we really only have two defenders guarding against the in cuts of all four of their cutters.
When the disc gets to the sideline, our mids are able to slide over and both play on the same half of the field that the disc occupies. The monster on the other side of the field is able to play a large area and make plays on any discs thrown in their direction while the monster on the same side of the disc is able to play the upfield throws directly up the sideline. It is really important that the middle handler is man guarded by the third member of the cup, so the only real option is a swing across the field to the opposite handler.
Notice everyone stays in the same order as they slide across the field when the disc is swung. The person in the wall that was just man guarding the middle handler is now marking the person with the disc on the sideline, the middle of the wall is still taking away the upfield throws to the middle of the field, and now the third member of the wall is playing man defense on the middle handler. The mids are now both playing on one half of the field, the monster on the far side has dropped down slightly and the monster o the force side has pulled back to play the deep throws directly up the sideline.
The only time the person in the wall will stop playing man defense is if the handler comes straight back for a dump. At that point, they will pick up the far side handler, who should ideally, move towards the disc. Essentially, this person is playing squirrel when the disc is on the sideline, and we will just reset the defense if a quick dump pass is made. Notice, that if a dump is made, the cutters downfield will generally be an extra 5-10 yards away, making it increasingly difficult on the offense to move downfield. As well as the handler who just threw the backwards pass being in the way , as there is now NO across field reset.