I think the gist is that you pick them up to calm them down, then the minute they stop crying you put them down again and leave, and repeat as necessary! I did try this with ds but it didn't work, mainly because picking him up repeatedly when he was tired just seemed to make him more cross. I found that going in and stroking his head and kissing him worked better and he settled much more quickly.
lyndyloo - agree with sweetjane. I tried this when ds was around 45mths and then again at around 7 mths. Cranked him up completely and he was utterly confused. I nkow it has worked for some but defo no good here.