how do you manage the mob mentality?

[bananahands]

Individually, I'm able to work with my kids in the ways that I want, and I think they understand our house approach. But when they are together (ages 5, 5, and 3) the climate deteriorates very quickly because their primary objective seems to be making the others laugh, using whatever means necessary. I'm at a loss with how to respond to this. I've tried separating them until the mood passes, but that just encourages them to continue the banter at a volume loud enough where the others can hear them throughout the house. (We've also had this alone time result in enormous messes in their rooms as they look for a way to release their frenzied energy.) I try to channel them to physical activities when it's possible, but I'd estimate about 80% of their together time ends up like this so it's just not possible to interrupt so much of our day with redirection. I was close in age to my siblings, too, and I remember many, many days of chaos and mayhem just like this. But I feel like it's derailing all my GD efforts. Advice, please!