If it’s something very serious, we both tend to go silent and distant for a short while. We always talk about it afterwards though.
If it’s something minor, I usually do something silly like this to lighten the situation. It almost always works :)
We used to press E.T.‘s tummy to make him talk (until he stopped working a couple years ago). How that started:
About 8 years ago (whenever it was that the film industry re-showed E.T.: The Extra-Terrestrial), we had bought a stuffed E.T. that said a few phrases from the movie and its tummy/finger would light up. We had been arguing about the house her parents had bought for the daughters to all live in (east indian cultural family) until they were all married off. To satisfy her parents, temporarily, she moved into this house with her two sisters for a few months. We were both upset (in my apartment) and I said something along the lines of “I just want you to come home” ..my foot was on the coffee table and so was E.T. ..I went to put my foot down and hit E.T., to which he said “Home, home, home!”. At that point we both started laughing uncontrollably and the situation was defused. We always had him out, afterwards, using him as a crankiness defuser.