Please, please stop pooping in your underwear. I know you're a big boy now and big boys put their poop in the potty... first. Not in their underwear and then the potty.
I know you can do this. And when you do (or doo), a super fun trip to the toy store and a brand new train await. Your mama isn't above bribery.
Oh, and thank heaven for the diaper sprayer. Sheesh.