For my body weight brethren and sistren, a common issue in completing overall development is a difficult proposition when a goal is in place to build muscle mass in the trapezoid complex.
There are several free weight exercises using a loaded bar or dumbbells that directly target the traps such as upright rows or shrugs, but from my experience it can be very difficult to stimulate the traps using strictly your body, unless your capabilities are of the slightly more advanced variety and you can perform handstands or handstand variations.
Dip Shrugs To The Rescue!
This movement is basic and effective. You simply hold yourself upright in the very top-end/eccentric position (ultimately holding the arms & delts isometrically.)
You then using only the traps, lower yourself being careful to take it slow controlling the movement.
At the bottom position, you then using only your traps raise yourself to the top once again.
Repeat. (I like to do these for fairly high reps to feel a nice pump in the entire shoulder girdle and traps.
I think there is also value in the isometric work that the arms and delts receive along with the increase of body control that will most definitely improve your dips.
See the video below for an example. (My apologies for the poor video quality.)