Make a consumable that forces character to poop

I’m making a mod with drinkable liquid mercury, which when consumed has a laxative effect. How can I force the player to defecate when drinking, or at least hurry that process along?

Adding this to the graph on a buff should work.

okay, but which graph? EventGraph of the buff?

And what do I attach that node to, in order to make it fire?

Event graph on the buff and use begin play to fire it. You could also probably put it on a looped timer to fire every x seconds/minutes if you so desire.