"gyaru-go" is the ganguru slang, gyaru girls use while speaking. on this page i'll explain 5 of them !
ks is like when you read someones text on line but haven't replied. kinda like "left on read".
yobaba is a variation of the japanese word, "yobai", which means to be dangourous, in trouble, or cool. yobaba is more cuter then yobai though. the more ba's you add, the more in trouble you are.
dekishi is an abriviation of dekiai shisugite shinu (to love someone or something so much you could die).
nyantsuku is a combination of nyan (meow), and tsuku (suffix that turns it into a verb). it pretty much means flirting.
hoshi just means "star" but in a "high energy" way. the meaning comes from nintendo when mario picks up a star and becomes invisible.
obierū means scared. not a new word, but gyaru tend to say it much more than the much more common word, kowai.
pikumin is like a cutesy way of saying you've gone to the toilet, or had to go.