I advise you not to use sculpting for this task, even if it is possible it is time-consuming and should make jittering effect.

Try to use Shrinkwrap modifier on cloth, *Snap mode* - *Outside*, *target* - the mesh body, increase *Offset* a little to start seeing the effect. 

[![enter image description here][1]][1]

Another useful technique, that's highly recommended by professionals, is to hide everything that's not rendered.

In the body mesh, add all points that's normally hidden by dress into a new vertex group. Then set up the mask modifier like this:

[![enter image description here][2]][2]

Note that mask modifier is disabled in viewport for baking cloth and enabled in render to hide parts of the mesh that's may intersect with cloth. 


  [1]: https://i.sstatic.net/jLDRR.png
  [2]: https://i.sstatic.net/1SALd.png