[Nebelherz]

Can anyone helping me explaining this. I have this sentence: おむすびと　かきの　たねを　とりかえっこ　しようよ 。 (I know it means: Let`s trade the Musbi with the kakiseed.) But what is とりかえっこ for a conjugation? (I mean the ending っこ . What does it makes to the verb and how do I build it)