How to get a grip.
There are several good ways to hold a Dremel rotary tool. Use the one that gives you the most control for your task. Or that you feel most comfortable with. One of these will work for you. 

THE PENCIL GRIP This grip offers the best control for fine detail work. 

THE PARING KNIFE GRIP Use this grip with cutters when making longer, smoother cuts. This grip offers good control for cutting depth. 

THE GOLF GRIP One and two hands. When you want to keep the tool parallel to the work surface for sanding or grinding, use the one-handed grip. Use the two-handed grip every time you use a cut-off wheel. Cut-off wheels can stick and cause kickback. Two hands offer better control. 

Remember, always use a light touch with a rotary tool. You're just guiding the tool. Let the high speed do all the work.