Watersports

My brother just came back from Japan and brought back these amazing pictures. Can you figure out what the product is? Is it a big yellow milk carton? A condom for men with rectangular shaped cocks? Or, is it a portable toilet? If you chose curtain number 3 then you are correct! Oh those crazy Japs. With my uncontrollable bladder I could've used this many a time. I'm just not sure how the little girl is supposed to use it...unless maybe it comes with a straw and funnel.