A clever way to insult somebody, especially a slutty girl. You can't get in trouble for this because teachers are so wrapped up in useless shit (see algebra) to realize that is you reverse the vowels in both words, you get Skank Bitch.
Blue-tongued skinks are the genus Tiliqua, which contains some of the largest members of the skink family (Scincidae). They are called commonly blue-tongued lizards in Australia, where true lizards (Lacertidae do not naturally occur. As suggested by these common names, its distinguishing characteristic is a blue tongue.
Did you know that the tongues of blue tongue skinks aren't venomous or even poisonous?