I also smoke mine at work at my desk, in Walmart walking around, in the mall, etc.
The vapor disipates quickly and only has a slight smell (depending on flavors added) and if you hold it for a longer time inside your mouth and/or lungs when you finally exhale there is almost no remnants of any vapor. Some mixtures have more visible vapor the others, also depndent on the type of mixture used. So in most cases you could, if you so desired, mask what your doing very easily.