http://www.youtube.com/user/24hrMrLocksmith

I just finished my first video to help people who are locked out of their bathroom or bedroom.

Locked out of Bathroom?
For a door that has a privacy lock (the kind with a hole in the knob on the outside), keep a tool handy that will open this door if it is locked by your toddler with you on the outside and your toddler on the inside. The tool can be made from a piece of coat hanger or a metal skewer from the kitchen drawer or the inside of a ballpoint pen. Kept handy, it could save you from considerable anxiety and frustration trying to get a toddler to unlock the door.
Put tool straight into the hole in the knob.
The tool will stop approximately 1 inch to 1½ inside the knob.
Gently but firmly push the tool just a little bit, approximately ¼ inch (you are pushing the spring loaded release button).
You should hear a “pop” or “clunk” as the lock unlocks.
Turn handle. 

Again, if the bathroom lock has a round hole take a wire coat hanger and bend it straight.  Stick it directly in the hole (straight and level) and feel for a springy button… when you feel it, simply push and it should release the lock.  
If this is not successful, make sure the tool is level and is dead center, or call me for help.