How to train a 3.5mths LO to STTN

I would also want to know too. But u have to know that 5 hrs is alrdy STTN alrdy. Don't expect longer - if it happens it's a bonus because it is not really possible, they will be hungry le. Anyway, there will be sleep regressions and disturbances from teething and growth spurts so why u don't need to be too upset if it doesn't work or work a while and u are hit w one of these. Within first year, its v common to wake 3-4hrly