Using a 1/4-inch round piping tip, poke three evenly spaced holes in the bottom of each baked eclair shell.
Fit the same piping tip into your reusable piping bag. Using a spatula, fill the pastry bag with the pastry cream. If you are using a disposable plastic pastry bag then just fill the pastry bag first and cut the tip to make about a 1/4 inch hole.
Fill the eclairs evenly into the three holes. Use a paring knife to clean any excess cream that comes out of the hole.
Fill the bottom pan of a double boiler with about 2 inches of water and place on the stove over a medium-low heat to simmer. Fill the top pan with your white chocolate. If you don't have a double boiler you can just use a medium saucepan filled with 2 inches of water and place your chocolate into a metal bowl placed on top of the saucepan.
Pour your shredded coconut into a small bowl large enough for one eclair to lay flat in. Also line a sheet pan with cooling racks to rest the eclairs once coated.
Occasionally stir the white chocolate so it melts evenly. Once the white chocolate is fully melted it's time coat the eclairs. Take one eclair, hold it flat with the holes facing up, and dip the eclair about halfway into the white chocolate.
Raise the eclair up out of the chocolate and let the excess drip off. Once the excess is done dripping we will go straight into the coconut. Gently lay the eclair chocolate side down into the coconut. Press lightly, remove the eclair from the coconut, and place on the cooling rack lined baking sheet to rest.
Repeat this process for all eclairs making sure to occasionally stir the white chocolate and adding more fresh coconut as needed. If you prefer less coconut on your eclairs then simply sprinkle coconut on the white chocolate instead of laying it into the coconut.