Two set patterns share this shape. The one ending in 겠거니 하다 is assuming something without checking, as in living on the assumption there are probably germs in there, figuring it was somebody else's problem, or guessing people would like it. The other is 주거니 받거니 하다, giving and taking, for a genuine back-and-forth between people: trading jokes with friends, or a thing that only works if both sides contribute.