To make the right calls for the bubble screen you need to keep the following things in mind:

1. Talent: Many times it comes down to utilizing your best talent on the field. This is why I emphasize that the Z receiver be your fastest receiver with good hands. He should be the guy you want to get the ball to. If he is a 4.9-5.0 40yd dash guy, it is going to be hard to hurt other teams as much with this package. I'm not saying that he can't get positive yards but to really scare a defensive coordinator into changing his game plan you need to have a real threat there. If you only have one of those guys, you may have to move him around with different packages or utilize motion or shifts to get him into position. The Z position in our offense also runs the fly and jet sweeps so his speed is utilized in the run game also. Having some speed at Z also helps with your H-Bubble Slant and Go plays. Make sure your QB is keeping his eyes on the correct defender when he is dropping back on the Slant and Go plays. 

2. Defensive alignment: I could get really specific with this but I think it is best to just keep it simple especially when you are in the middle of a game. The simple rule to follow is to look for the numbers advantage below the flood line. The Flood line is set at about 7yd depth and defenders that are below it are primary threats to the bubble screen. Defenders that are above it are too far to away to be a threat. Their coverage responsibilities may also put them at a disadvantage to stop the bubble (ex. Deep 1/4, 1/3, and 1/2 players). As long as the bubble receiver is either uncovered, or someone is blocking the defender over him, you should throw it when you have the numbers advantage. When every receiver is covered with a defender below the flood line, the H-Bubble becomes your best option because you have hat on a hat blocking on the perimeter. When you are game planning and scouting opponents, look at what they run in different situations. If a team likes to jump to man coverage around the goal line, know that your Bubble may not be a good call, but Bubble Slant  or H-Bubble Slant may be perfect because you can get a one on one with your best receiver inside with good leverage. 

3. Bubble Slant: Before you call a Bubble Slant, you are looking for aggressive linebackers who are coming up hard to tackle the bubble route. You are also looking for a clear path to throw (ex. man coverage). This is why I like to call my Bubble and H-Bubble early in the game to set up the Bubble Slant. If a team is disciplined and drops into coverage, you should be able to run the base bubble screen play effectively. 

4. Bubble Go: The key to calling the Bubble Go is to find a time when you have room on the field and also when you see deep coverage defenders cheating up or reacting too quickly to the bubble screen. It is the kind of play you have to set up first with well executed bubble screens. I might call this maybe once – at the most twice – a game.  I also wouldn't take a shot on a third down or in longer yardage situations because you want defenses to not be thinking as much about stopping the deep pass. 

5. With teams that like to switch up coverages and alignments on you, you can call Bubble Check. Then when the offense is on the line you can give the hand signal for which bubble play you want run. Here are some signals that are simple and easy to use:

Bubble – Just hold up your hands in a circle or O shape. If you want it to the right side you can give an a hand wave or thumbs up, if you want it to the left, hand wave down low or thumb down. You could also have your QB throw to the side that looks best and have both sides run the bubble screen like they are going to get it. If you do this just make sure your RB doesn't get in the way when you are throwing to his side. He needs to come up and attack the Line of Scrimmage with his block on the end. 

H – Make an H signal with your thumbs together and forefingers up.

I like the idea of picking themes for your packages. For example using Natural Phenomena for screens. 

Bubble = Thunder = Hand Clap

Bubble Slant = Lightning = Zig-Zag hand signal.

Bubble Go = Tornado = Spiraling hand signal.

Whatever you pick is not critical as long as everybody knows it. 

One of the easiest ways to call the screen is to simply send in a number. If you send in Trips Right 3, it means you are throwing Bubble Screen to the trips side 3rd receiver. In Doubles (2 x 2) formation if you send in a "2 Right" call it means the 2nd receiver counting outside in on the right side is getting the ball on the bubble screen. A "Doubles 3 Right" means the H is getting the ball since his is the 3rd back in. Combine this with motions and players could know that when the ball is snapped, whoever is the 3rd receiver in on a 3 call is the bubble receiver and all the others are blocking the most dangerous defender for him. This is a great way to run a super up-tempo fast offense and get the play in very quickly. 

When running the Bubble Check, make sure your O-line knows that they cannot get downfield on Bubble Go. You may want the QB to give them a call to remind them. With H-Bubble Go the protection needs to be changed to a 5 man dropback scheme. With Bubble Slant, they should block it exactly as if it were a bubble screen. The ball should be out quickly enough that they do not have a chance to get downfield illegally yet.

6. Run-Pass-Option (RPO): This is where you add in the Bubble Screen Package with your running game. This can be extremely helpful when you have edge blitzing linebacks that like to stem or delay their blitzes or move around a lot. As a coach you may be guessing when to call the screen vs. the run. When your QB reads a linebacker, the linebacker is called the Key. This makes the play a Key Screen. The classic example of this is a Zone Run to the Right (HB lines up on the left) out of Doubles and with a Bubble Screen to the backside. The QB keys the outside LB on the backside for either a run or pass option. Your line is blocking all 5 in the box – there is hat on a hat. The classic 4-3 defense has the Sam and Will LB splitting the difference between the #2 receivers and the Tackles. Both of them are considered in conflict. If the LB on the backside comes down into the box before or after the snap for run, the QB throws the bubble screen because there is a numbers advantage (as soon as he knows where the best option is, he should execute that option (do not hold the fake out there when you don't need to). If the LB stays wide and away from the box, your QB hands the ball off. 

7. Blitz Audible: You could also have an audible to the bubble screen if the QB sees an edge blitz coming pre-snap. The Bubble Slant and Bubble Go also work really well with RPO's. An example of this is a Zone or Power Read to the right. If the LB comes down, the QB pulls and throws the Slant behind him. Just remember again that your run blocking scheme cannot get downfield when you are passing the ball deeper and it takes time for the ball to get out. This is a great way to incorporate the option offense with a QB who is more of a thrower then a runner.