If it were me I wouldn't tuck in my weak side outside mid....instead....teach your right back (if the ball is on the right mids foot) to push up in a supporting position as your back line shifts over. It would look like this:

                                                    RM (w/ball)

           LM                                      RB

                      LB      CB       CB

  That is pretty rough....but you can see that the RB can step in and apply pressure while the back line shifts to cover...at the same time you delay the ball the LM can get back in the play and join your defensive line.

AA

    Yah...I was too lazy in putting the positions in....but normall with my mids I would want the them to make a nike swoosh almost, then I instruct the left mid to look to get his heels on the line as soon as the ball begins to come near him

AA

We did this at the end of every single practice on a full field.

We break up the team and play a game on a full field. Very important to push the players to retreat to the defending half of the field if we lose the ball.

Except the upper most 3 players. Player closest to ball and dribbler pressure that player. Farthest up field player takes away the

 dribblers closest back pass option, and the other supports the first defender. If ther ball get's by the first defender the second defender takes the player closest to the ball and the first defender becomes the second defender behind him.

When the rest get behind into our defensive half of the field they also retreat into that part of the field.

If by chance the upper most three get the ball back. Then we have a three man counter attack.

Totally agree Bob. The idea that FORMATIONS change as suggested in the question and that a player in a particular position should always 'tuck in' is trying to play by rote.  There are far too many variables for that kind of approach. In general, a defensive mid is often required to plug holes at the back to maintain balance but is just as likely to be a first or second defender.

My main concern with the diagrams is they give no clue as to which part of the field is being defended.  Is this the alignment on the edge of the 18, the half way or what?  What is the overall team tactic? Is this the alignment when we are asked to defend high pressure or low pressure? 

Over time I continue to be disappointed by the continual references to formations rather than to shape.  Watching Arsenal (since I got Fox this year) I have marvelled at their so called 4-5-1 formation.  Just this week, Kolo Taure ( a centre back) ran through the centre of Liverpool's defence to latch onto a through ball to score an excellent goal.  Flamini, nominally a defensive mid in their 5 man midfield also scored from close range. 

For each player, transition duties depend on where you are when the ball is lost. Where would these two players have gone on transition if their goal attempts had been saved?

Let me suggest one other way to look at this.

Ogranization is important and principles of play will guide players' actions, but another way to look at how your players align themselves is to use a few other quick aids to thought.

First, players within roughly 20 yards (adults, adjust down for younger ages and for adults with less skill) of the ball will position themselves in relation to the ball.

Second, players further away will position themselves in relation to the position being taken by their opponents.  The defense balancing and filing passing lanes and the offense seeking support positions and width to create passing options.

These are not absolutes by any means, but they are a short hand way to look at your alignment and see quickly who is not in a proper position for the given moment of play. 

Thought of this way the position of the defensive mids is dictated by a factor not show on any diagram - the position of the attacking team's players at the moment of transition and immediately thereafter.