I haven't had much luck with "feeding" sticks...I've used the clear acrylic ones you can get at the LFS and the long tongs...
It seems to me that "waving" a chunk of food in front of a fish causes more stress than eliciting a feeding responce...
And I have tried the subtle approaches and "lifelike" manouvers...
When I did get a fish to "strike" more often than not they would hit/feel the stick and drop the food.
To get your shark to eat (as well as the above responses) you may want to try "leading" the shark to food...
Thaw a cube of "ground" squid and suck it up a turkey baster...then squirt a small amount in front of the shark...he should move forward a bit and eat it...
Eventually you can "lead" him around the tank with squirts of food...as he starts to associate the 'smell" of food with eating you will eventually be able to elicit a feeding/hunting response just by "swishing' food in the water column.
At that point he will hunt down and find most anything you put in the tank...