Hello mll24242: The child probably saw something of this sort somewhere, perhaps on TV or in a movie, etc. Children are inquisitive & impressionable. So she decided to try it out on her dog.

Of course there are potential health concerns here. So she needs to be instructed that this is not a healthy thing to do. But beyond that, from my perspective, it is important not to make a big deal out of this! Over-reacting, shaming her, could well do more harm than good.

If you know the child's parents you might tactfully mention what you know to them, in case they're not aware of it. But, really, it's important, in my opinion, to handle a situation like this delicately & not over-react. Please try to avoid being shocked...
I see this is your first post here on PC. So... welcome to PsychCentral… from the Skeezyks!

I hope you find the time you spend here to be of benefit.
PsychCentral is a great place to get information as well as support for mental health issues. There are many knowledgeable & caring members here. The more you post, & reply to other members’ posts, the more a part of the community you will become.

Plus there are social groups you can join & chat rooms where you’ll be able to connect with other PC members in real time (once your first 5 posts have been reviewed & approved.) Lots of great stuff! So please keep posting!