How soon is too soon?

The past few days Porter has wanted to sit on the toilet and pretend to pee.  He wants his diaper off, he pushes his penis into the toilet and then needs toilet paper to dab himself when he's finished.  

Today he actually stood next to the toilet and using the straw string in his shorts he aimed it into the toilet to "pee".  Hilarious.    

Maybe he'll be potty trained by the time baby #2 comes along.  I'm not expecting that, but wouldn't that be a pleasant surprise:).