Oh gosh, that's a hard question....
Probably after hours of torture. Killing their loved ones in front of them first, to get in the right mood. Then bending their little arms backwards until they break and shoving a claw in the spot where the bone fractured. Then you just pop them in your maw and chew them up slowly, or you show them how much your paw weights...
Honestly this is just one of the ways to do it, there are basically infinite choices :3