Cut the whole loofah into strips that will fit neatly into each cavity, then place them in the silicone mold.
Chop the melt and pour soap into cubes, then place it in the top of the double boiler. Heat the soap over medium-low until it's completely melted and clear, stirring frequently.
Once it's completely melted, add several drops of soap colorant. Stir, then continue adding more until you get your desired color intensity.
Next, add essential oils until you get your desired strength of scent and stir to combine.
Immediately pour the melted soap into the silicone mold over the loofah pieces until there's enough soap to just cover them.
Allow the soap to cool and dry completely, then pop your loofah soaps out of the silicone mold. Wrap tightly in plastic wrap. Place your wrapped homemade soap bars in a mason jar and use them one at a time in the shower or gift them to a friend.