You break it up into the three (for the shortened version) or seven (for the full version) segments per vibration. You would, for instance, do the "A-U-M" in one segment--I believe the JoS site has MP3 files in the Sermons section just below the "Audio Sermons" heading. For a Sun square full version, for instance, "A-U-M" is one segment. H-R-A[stutter]A-M" is the next segment. H-R-EE-M is the next, and so on. You are permitted to take a brief pause between each of these segments.
And listen to the MP3 segments. Nothing like spending 10-15 seconds vibrating each segment when 2 seconds is sufficient to do the job. Not only will prolonged vibrations not work better (and they may even ruin it), but you are wasting time. This is particularly important when doing a Moon square--unless you like spending 90 or more minutes doing your 81 vibrations on the longest day, it is helpful to get the timing and pronounciation right. And no, if you get short of breath, that's what the pauses between each segment are for.
