When applying grout to a small area, you will find that a grout bag will come in very handy. A grout bag is the way to apply grout to an area where you need a small amount, the grout will stain the tile, or it will be difficult to remove once it has dried.
Mix Grout in Separate Container
When using a grout bag, mix the grout in a separate container. This will not only make it easier, but will also allow you to get it to the right consistency.
Many problems are caused by people filling the grout bag all the way. You do not need to pack it full. Fill the grout bag about 1/3 of the way. You can handle the bag much better and be able to focus the bead where you want it.
Once you put grout into the bag, shake it to relieve any air pockets.
Apply Consistent Pressure
Hold the grout bag at a 45° angle to the work surface and apply pressure to the top of the grout. This will lay down an even bead of the grout instead of gobs of grout. Move the grout bag evenly across the area and lift off the surface when done to create a hard break.