The first time I thought of juggling for goalies was when I watched the movie Miracle on Ice about the 1980 US Olympic hockey team. In that movie, they had a sequence where the character playing Jim Craig was seen juggling balls off the floor and wall in a hallway before the game.
It was there that I realized that the peripheral vision that is built up from juggling is critically important for goalie development.
Having said that, I am NOT a juggler. So, I will include multiple links for you to start to practice and strengthen your peripheral vision.
Note her straight back.
She is adamant about the back being straight and not leaning forward.
One thing to consider: ALL 1 and 2 ball throws can be done in an overhand throw to keep the hands up.
The 1 ball wall ball ideas can work to use ONLY the upper hand in an overhand position and do the wall ball rotating between right and left shoulders.
Queen City Girls Lacrosse - from the coach's perspective 