Not oh crap although I don't mind incorporating some bits from it. The one where you give them loads of juice and take them to the toilet every half an hour.
Would you big it up beforehand or just announce it on the day? Pretend the nappies have run out? How long before? Child is somewhat prone to anxiety.
Rewards yay or nay? Some kind of sticker chart? Don't normally do these but I think it's a good time to break one out - specific measurable task that's temporary in nature.
I know he can do it, it's just persuading him to ditch the nappies. 3.7yo neurotypical, has done wees and poos on toilet before and prefers privacy when he does it. We are not on a deadline, just fed up of doing nappies now.