Though the exact meaning of dabadee cannot be expressed in mere human words, the meaning lies somewhere between "oh well" and "it's all good". Typically used when things are FUBAR, dabadee is a way to shake it off and carry on.
professor: "You only attended 2 classes the whole semester. I'm afraid I'm going to have to fail you."
you: "Dabadee" *shrugs shoulders *walks out
Hey duder, have you seen Scott around here? That guy is SUCH a prick! I wouldn't go so far as to call him a douchebag, but it's close. He's definitely a dabadouche.