Stick a water bottle in the pack and shape a command for something like "bring me water". Make a fuss every time you get the bottle out and take a swig. She will get the picture that she is bringing you a wanted item. Or even better make the pack the focus, so it's like "I need the pack, girl" and then make a pointed commotion of opening zippers and the like. A cool add-on would be a command to turn around to access both sides. I taught my old guy to "gimmie your butt" so I could massage his rear legs.
Never cook bacon while naked.