It means when you hold the shift key down for too long and as a result, you end up with two capital letters where there should only be one. Derived the fact that if you do shift+1 and shift+2 you get !". Commonly found in names.
NOTE: The names in the example are just roleplay characters, not people in real life.
A 'fag-hag' is a close, often homosexual friend who happens to be the opposite sex. One who has little to no chance of becoming sexually interested in you, largely due to orientation. This often allows for a platonic bond far closer and deeper than conventional friendships.
Useful if a person wishes to fool their parents about their orientation. The fag-hag will be introduced as their friends' boyfriend or girlfriend.
I heard person A telling person B that person C went and got themselves a fag-hag.