DS turned 2 in February, his understanding is quite good (he says "mummy do wee, mummy toilet" when I use the toilet) but every time I sit him on the potty or toilet he says "all done" instantly and gets straight back up. He seems happy about it, and will go back on a few times with encouragement but stands up within 1-2 seconds each time then gets frustrated and won't go on again after a few times trying.
I try to get him to sit on each time I go, and before the bath to familiarise him with it, but he's still not done a wee on it. Or even sat on it long enough to really.
Does anyone have any advice?