DS really wants to wear his underwear- so we did it yesterday and I put the plastic training pants on over top. It ended up being a mess- I got a 2T size (the Gerber brand) and we had leaks every single time plus they looked huge on him. DS doesn't mind peeing/pooping in the pull-ups so those are a waste. We'd go potty every 15-20 mins but a few times we couldn't get to the potty fast enough. Anyways- any recommendations for training pants? Other things to try?