Ah, sticky highs. Here is my opinion about what happens:
Our body continuously releases glucose into our blood stream; it has to do that because we need energy continuously. The body of a NonDiabetic continually releases insulin to allow the glucose to be adsorbed. We T1Ds have to inject insulin instead; this is the basal dose.
When we get stressed, possibly just by an incipient illness that we don't even notice, our body releases more glucose to provide energy for dealing with the stress. NDs produce more insulin in response, T1Ds either need to do the same, by increasing the basal dose, or need to remove the stress.
If we do neither we get a sticky high. That's because a correction bolus takes about 4 hours to act and, over that period of time, our body has released a whole load more glucose that we haven't got the insulin to handle!
I typically handle sticky highs by multiple corrections spaced about 2 hours apart, but that only works for me because I have a 2 hour insulin action time, so I end up stacking the corrections. A more logical approach is to use a temp basal *and* a correction then avoid stacking the corrections by waiting 4 hours before doing anything else.
The easy way to do this while fasting is as follows:
1) At least 2 hours and preferably 4 after your last meal do a blood test and correction bolus using the PDM calculation.
2) Wait 4 hours, don't eat ;-) Do another blood test and correction, but now take the correction bolus, divide by 4 and use that as an increase to your basal for 4 hours; i.e. do a temp basal which will deliver exactly the same as your correction bolus over the next four hours.
3) Check again after 4 hours. You have apparently double-dosed (notice that this is like what I do with my short action time) but really what you have done is correct for the previous 4 hours of too-low-basal and anticipate the next 4 hours!
Once you get the number from (2) you can eat again, immediately, but don't do another meal bolus (or eat) for 4 hours; until you get to (3).
We need to keep up the temp basal as long as the stress continues. Since we aren't likely to know when our body stops responding to it the only thing to do is test frequently; I'd say at least once every 2 hours. Don't be tempted to correct until after the end of the insulin action time programmed into your PDM (and take care if you do what I do!)