Necro- I think you are a Kinesthetic Learner. Learn best by doing.
Slither- The latest is that once you double pass on something that has a window, or a definative Step you must go to after a sub-step, that something is over.
Some examples: You both agree to enter the Main phase. You have priority to Summon, Play SS1, attampt to End Pahse. You summon, then pass on your priority to negate your Summon. Opponent passes (Neither can negate the Summon anymore, window closed). You pass on your response to the Successful Summon. Your opponent passes (response Window is now closed). You (TP) can now activate a SS1 Spell Card, end MP1, or whatever. However, at this point, if you choose to pass and your opponent passes back. You do not, then, imediately End MP1. You have a choice to go to your Battle Phase or End Phase. However, you, the TP Must do something now; either activate something or attempt to End MP1 (This will become clearer when we look at the end Phase).
You attempt to enter your Battle Phase. NTP agrees (you still cannot attack yet....). You pass on activating anything for the Start Step. Opponent Passes. You must now either activate something or attempt to move to Battle Step (or End Step of the Battle Phase if you do not want to Battle). You do not automatically end the Start Step; also you may activate and resolve several chains during this Step. If you Enter your Battle Step you can either activate an effect/pass (but who ever passes? Multiple chains can form here as well), attempt to end Battle Step, or declare an attack. If you declare an attack there is an attack Response Window (sub-step) that a double pass will miss.
Once that is cleared, you enter the (pre-Damage Step) Battle Response (sub-step) in which you also can have multiple chains which can activate and resolve like the Start Step; However, unlike the Start Step, where you have an option of where to go after a double Pass you do not have an option of where to go next. If you double pass during the Battle Response (sub-step) you move right into the next full step: The Damage Step. Pretty much everything within this Step has a Response Window with double passes missing all oportunity. When that Step is over, you are back in your (post-Start Step) Battle Phase and TP has Priority to activate something or declare another Attack.
Overall, it appears that sub-steps miss on double-passes, but full steps do not. I believe that this is because of the fact that you have choices as to what the next Step is that you will move into. This is especially true with whole phases.
For instance, let's say that in the End Phase you and your opponent have several things attempting to resolve. You want your opponent to resolve his first, so you pass. He does not want to, so he passes back. Now you are stuck. You have to resolve something. Now that you have, whose turn is it to resolve something? Not his!! You are the Turn Player. You go frist. You can try to pass, but if he passes back, you must do something. He can wait until all your effects waiting to resolve are spent before he has to resolve even one of his effects (the exception being those one or two cards--oneof these days I will look them up--that require them to be the absolute last thing to go off. Everything else, whether it says begining, during or whatever happens when you decide at some point in the End Phase).
Now, I know I covered more than just the Battle Phase, but I felt it was important to get the whole feel of the thing. So, if moving out of a phase, a double pass won't force you out. If moving from a Step, where you have options as to where to go next, it won't force you out of that Step. However, in sub-steps a double pass will force you to the next (sub-) Step.
Anyway, this was the latest I have. We may get more stringent rulings that state that even a double-pass in the Steps will Force you to move to either the next Step, or end the Phase. However, if they have come up with that, I have not heard of it, yet.
