Trade him playdoe or something else squishy to play with.. it may be the way it feels to him that he likes... Just a thought...
Does he play with spaggetti too? what about peanut butter? I think it may just have something to do with what he's learning about what his fingers can doo.. sorry couldn't resist...
Cheers, Tamra
Welcome to motherhood. No, there is nothing wrong with him. But you might consider watching him more closely so that he doesn't get a chance to decorate your house. You might also sit him down and explain quietly that big boys don't play with their poop and therefore he can't. Tell him It isn't right.