When making a cookie or graham cracker crust for a no bake pumpkin pie or any other no bake dessert, first make sure all of the crumbs are fully incorporated and moistened with butter. This will help the crumbs stick together and to the sides and bottom of the pan or pie plate. Also, firmly pressing the crumbs (try using the bottom of a measuring cup) allows the crust to stick together well. Lastly, we recommend placing the crust in the freezer to help firm up prior to adding the filling.