My wifes family practiced whistle training, and helped do it with our kids. Immediately, from birth, whistle when the kid is peeing. Try to catch them in the act every single time and whistle. Its exhausting. But, seriously, after 2 weeks, the kids never piss or shit themselves again. You start a regime of taking them to the potty or toilet or whatever and holding them ready, and whistle...and they just go. No nappies. Potty trained from birth. Its not perfect, and its hard, but the effort lasts for the baby years, and is well worth it.