Tag alias: pierced_labia -> labia_piercing

aliases:
pierced_labia -> labia_piercing
pierced_ears -> ear_piercing

implications:
*_piercing -> piercing

i guess we could get rid of genital_piercing in favor of penis_piercing etc. -- if not there would be some more implications

I've cleaned up genital_piercing to fit in either labia_piercing or penis_piercing, so we can ignore the tag if we wish.

Otherwise, +1 on the two aliases and implications.

Done