Line an 8 1/2-inch x 4 1/2-inch loaf pan with parchment paper. Allow the extra paper to hang over the sides of the pan. This will help you lift it out of the pan later.
Unwrap three of the ice cream sandwiches and cut one in half. Leave the other two sandwiches whole.
Arrange the ice cream sandwiches in bottom of the prepared loaf pan. They should cover the bottom of the pan completely.
Top the ice cream sandwiches with about half of the Cool Whip. Then spread to cover the sandwiches completely. Sprinkle the crushed Oreos all over the Cool Whip layer.
Unwrap the other three ice cream sandwiches and cut one in half. Layer the ice cream sandwiches in the same manner as before, and then push them down gently. This will help the Cool Whip squish all over the sides of your cake.
Top with the remaining Cool Whip and spread it edge to edge to cover the cake completely.
Cover the pan with plastic wrap and place in the freezer for at least an hour until firm.
When you're ready to serve, remove the pan from your freezer. Lift parchment to remove the cake from the pan. Peel the parchment paper off the sides. Use a spatula to transfer the cake to a serving plate.
Using an offset spatula or butter knife, smooth out the Cool Whip spreading it to cover any areas that need more coverage.
If desired, garnished the cake with sprinkles, crushed Oreos, chocolate sauce, or caramel sauce. Cut into 6 slices and enjoy!