You can actually engage with the game and go through the whole thing (it's kind of like a parody, and interesting enough) or just use the "chapters" section on the map to head for chapter 6 and the bad girl.
You can stab her, stab her after getting her undressed, or perform an execution by deep throating failure. Alternately, you can wind up dying to her (sadly, no graphic scene).
Weird note - the latest version of the game linked above makes quite a few changes. Some of the worse once involve omitting the actual licking scene and the Sardukar troops hilarious reaction. You can watch the original scene at 17:20 here: Behind The Dune V 2.4