To use couplers in disposable bags, first trim a little off the end of the bag.
Insert the inside section of the coupler in pastry bag.
You may need to trim bag again with scissors.
Place decorating tip on the outside of the bag and coupler.
Screw ring down on coupler to fasten tip on tightly.
Coupler and decorating tip are attached. Bag is ready to fill with icing.