Neptune at the ASC suggests 'you might express yourself artistically and may come across as gentle, sensitivity and dreamy;' read more at
http://www.cafeastrology.com/articles/neptuneinhouses.html
Neptune is co-ruler of your 3rd H showing it is especially related to your Mind and Communications with others. You are very sensitive to your environment, and may pick up on subtleties that others miss; you are also apt to pick up on
psychic vibrations that can cause confusion for both yourself and others; your perceptions may often be at odds with others as well, yet your intuition may be quite strong.
As waybread pointed out, you can come across as the chameleon, adapting your personality to different social situations, so yes you can project yourself as you wish to appear. Your projection of self can make you appear naïve at times though, or overly innocent.
You may easily be drawn to music, poetry, romance; your dream life is probably quite active, as a messenger for your inner self. With all your Scorpio energy in the 12th though you may be subject to secret enmity arising from issues of power and control. This may well serve to create scenarios of betrayal or deception, which you need to protect yourself from. Neptune also relates to trust issues, so right action and self-awareness may be part of your karmic agenda.