when ur best friend is crusty, u have lots of snots in ur nose that constantly cause u to disturb everyone around u by "cleansing ur nasal fluids" in the loudest and most irritating way making others laugh and feel awkward and uncomfortable, and pigeons r annoying and somewhat diseased, so u have that in common.
a girl who looks like she constantly is giving some type of sexual favors to others. also dresses and acts like a hooker. therefore, making her a slutfaced hooker!