If I catch Chloe in the act of doing something bad--chewing something she shouldn't for example. I'll give a sharp "NO!" If I find something she did bad, that I didn't catch in the act, like chew the beads off my new flip flops
!
then I do this long deep voiced "oooooooooooooooooohhhhhh". It sounds a bit like howling. She starts rolling on her back when I do that.