We are trying out some new underwear... they are really training pants, but they are like underwear.
I don't think Jackson really knows a difference between underwear and diapers. I think what he really likes is to run around with neither on. Which I've been letting him do a lot lately, especially since it's finally warmer out. And since we've been doing that, he'll go pee in the toilet more and will now do the diaper sign for most poops before he has gone and we make it to the toilet too. He's signed diaper a couple times for having to go pee, but most of the time I just take him to the toilet every so often if he hasn't gone outside or on the linoleum lately.