It isn't so much positioning as it is execution. Skill development is essential.
3B and SS have to learn to throw the ball from the position they field the ball. They have to learn to throw without repositioning their feet. So, these girls have to have really strong arms.
3B has to learn to cut off the slow ground ball to the SS and to read the bunt.
C has to learn how to rake.
1B and 2B have to learn to stretch, RF has to learn to backup 1B.
You have to define "who gets what" and how much you are going to have P cover. (In HS, my DD covered all bunts because she was the best fielder out there. In college, she covered only bunts directly to her.)
Coaching 14U the right defense for the slap needs to be the right defense for your specific team. It's important to identify what you have and don't have.
Is your 1B 6'0 and slow and your 2B is 5'0 and quick. Many teams will play a 1-back defense with that on the field where the 1B stays home and 2B moves into a position between pitcher and 1B to cover that side.
Is your pitcher a good fielder? Is she left handed requiring a pivot to throw to 1B? that will dictate how much territory you let her cover.
The reality is that for a skilled slapper, no matter what defense you set up there are obvious holes to shoot for and it comes down to the offense and defense's ability to execute.
Mark H that is funny. Only one I disagree with is the Rise. Billl Hillhouse in his DVD Riseball suggests not to throw a riseball to a slapper, since they have the eyes high as they come out of the box and can see that pitch. I will add if you play 2B or SS deep a good slapper will beat you every time. A good slapper takes what the defense gives them and also can power slap over the defense if they are playing in. Keep in mind they just want to get on first, because they know after a few pitches if they have speed, they are on third.
Those locations are good. They are even better if the ball is breaking down and in or up and in to get to those locations. Away is very good if you are throwing a left handed curve. Ask Gary Haning about that one.
Inside is actually easy for them to adjust to as they are moving and can step away from the plate and turn inside pitch into a middle pitch.
Outside low is usually toughest for most girls because they get "happy feet" and want to pull away from the plate and head to first before making contact, or they turn their head off of the ball to early making it tough to hit the low outside pitch where you need your head on it the longest and you need to keep feet on the front of batters box line.
For some slappers (who tend to drop their hands to early) then a high outside pitch is effective because they can't stay on top of the pitch.
The whole exercise from both sides of the plate is about execution. There is a defense for any 1 individual slap, but a different slap for any individual defense. Defensively you are basically playing the odds: Lets just say a good slapper can get 8-9 out of 10 pitches down for soft bunts. They can stay on top of 6-7 out of 10 pitches and drive the ball hard into the ground, 4-5 to the location they choose. But when it comes to driving the ball in the air with any form of power their odds drop to normal batting average 3-4 out of 10 at bast. You play the odds and take away what gives the slapper the best chance to get on and if she executes the opposite of what you were playing to protect against on the pitch that shouldn't let her do that ... you tip your hat to her.
You want to defensively do the same thing that she does offensively ... keep records. Here is our plan, we play ball, we face 10 slappers then we say "we got 2 out of 10 slappers out" our plan is terrible lets make an adjustment. Then we use that plan until we face 10 more slappers. This new plan got 7 out of 10 slappers out, now we are cooking that is a good plan lets keep it. But just like she would do on offense you have measure AVERAGE, you can't measure your success/failure based on the first slapper getting a hit and saying "wait this was a terrible plan we need 2B to play in instead of the 1B."
RH drop curve is Ernie Parker's favorite pitch against slappers. Works for me as well as just a rh curve against slappers. I'm speaking of good slappers who don't pull off toward first. If they do it's a given you go away and maybe off speed. Forcing a ground ball on the right side of the infield is usually a good result against slappers. Foul ball on the drop curve is even better. I don't like any pitch up and away against any hitter but I really don't like it against a slapper with that hole behind F5 where those really annoying bloops drop in. But then I haven't worked that pitch against slappers so if it works for you it works for you.
As an aside, against hitters in general I like the low corners, jam them or of course anything out of the zone they like to chase ineffectually such as at the eyes. Course you have to know your hitters. Throw Gomez at the eyes and the pitcher probably needed a new ball.