S.G.
i just bought my 20-mo a potty seat a month ago or so. i have taught her what 'sit on the potty' means and what 'wipe your tushie' means. she will sit on hers when i go. i always cheer. she also has recently become obsessed with toilet paper, so i give her a square and tell her to wipe her tushie when i do. she is fully clothed, but at least she gets the concept/command. i've had a lot of friends tell me their kids were interested at this age then became disinterested at some point. i work with a nurse who did the every two hour thing. that works if you're home all day. i know someone who did the no diaper thing. all 3 of her potty-trained boys are now bedwetters. every kid is different. you could take advantage of the nice weather and let him run around in the backyard with no diap. my nephew will be 4 in june and is not fully trained, yet his 2 year old brother is doing great. go figure! good luck.