Take the thread, cut about 10 inches off, take one end of the thread and fish it through one of the holes of the earring.
Create a loop, tie it together.
Then put the bobby pin into the hole.
Put the earring on normally and then take the bobby pin, which is now connected to the earring via the thread, and pin it into your hair.
Take the bobby pin and clip it somewhere into my hair further up, this takes off most of the weight of the earring. Cover the thread with your hair.