Nothing remarkable about "slippy":

<i>The door was open wide, with silver moonlight shining through,
The place was wet and slippy where she trod.
An ugly knife lay buried in the heart of Mad Carew,
T’was the vengeance of the little yellow God.</i>

My parents were from Western PA. They said, redd up, poke for paper bag, gum bands for rubber bands, 'greazy' for greasy, nightwork for homework, etc. I can tell a Western PAer from the first words out of their mouths. They all sound like my parents, grandparents, and cousins.