Basic setup. 1 is always the mark and always marks straight up. Has to be quick and a good mark. 2 and 3 are the WINGS - their job is to cut off the up-field throwing lanes that are to either side of the straight-up mark. 4-6, the MIDS, and 7, the DEEP, have similar jobs to a traditional 3-3-1 defense.
If the disc is swung horizontally to another handler, the cup retains its shape and shifts over. The WING on the far side (4 here) may pinch a little to discourage a full field swing, but this is a judgement based on what throws are likely.
The disc is swung back to the middle and the cup follows.
If the disc ends up on the sideline, whether due to a swing among handlers or a pull, a *TRAP* called by the mark. 1 (MARK) puts on a hard upline force. The WING closest to that sideline (2 in this case) takes away the upline lane and the other WING (3 in this case) stands off the mark to take away the easy swing pass. (If the disc is on the other sideline, the roles of 2 and 3 reverse.)