Add all "dressing" ingredients and mix together until all is well moistened. If you feel it is too dry, add a little more mayonnaise or another Tbsp of sherry and mix.
Once mixed, either proceed to stuff appetizer sized mushrooms (approx 2" across), place on parchment lined baking tray and bake about 12-15 minutes at 300 degrees. Check to see if the shrimp are pink and cooked. You can top with buttered panko crumbs mixed with chopped parsley to decorate and broil til browned.
You can also cover the mixture with film and store in fridge until needed. This should make it set up some and help with handling the soft stuffing.