My 3 year old boy has taken to potty training fantastically (still the occasional accident and far from ready for no nappy at night time, but we've only been going at it 3 months). We're starting to get brave and not take a potty out with us as he'll comfortably use a public toilet for a wee.
However, the poo's are going to be a different story. He amazingly did a poo in a restaurant toilet recently, but with the use of our adaptor seat that reduces the size of the toilet seat. I can foresee a time where we might forget to bring it along and I was wondering if anyone had a technique of how to sit him on a toilet for a poo without him falling through! For wee's I just sit him a long way back and I hold onto a leg so he doesn't fall in, but if I do that for a poo it's going to be very messy.