Muffle Bug

The indecent of a nark about to nark on a 'bad' thing. And then just as the nark is about to say the 'bad' thing a 'good' person jumps in and puts their hand directly over the nark's mouth and puts in a fake 'good' story to cover up.

Nark: You see, Matt and Joe were drinking b--

*Matt lurches at the nark and puts his hand over his mouth.*

Matt: B-beverages! we were drinking certain beverages!

Joe: Yes, yummy beverages!

Nark: Dude! You Muffle Bugged me!