Put your hair up while WET, and smooth a bit of gel through the length once in a pony tail. Learn how to use the correct hair pin in the correct way for your hair texture, there are about 14 different hair pins, ranging from bobby pins, roller pins, hair pins, amish pins, hair forks, etc. Then cover the bun with a hair net close to the color of your hair to keep all the whispies in.
By saying you like your bun to be on the top of your head, I certainly hope you're not putting it any higher than the crown (right where it curves, and the top is no longer the top, but the back is no longer the back either..that's called the crown) Even most Balanchine dancers don't put it much higher than the crown.
Also, try using more than one section of hair, like how you make a braid. Try with 2 strands of hair, and make what is called a "vortex bun" if you can...you can view my videos on Youtube (search for CinnamonCurls or vortex bun) showing 3 and 4 strand vortex buns, you should be able to understand a 2 strand one from them. Or just braid your pony tail before you twirl it into a bun, the braided strands will help hold the whispies in too!
retired professional ballet dancer who loves Balanchine height buns.