His statement is seen as an attempt to 'climb down' [='back away'] from the strong denial he made yesterday.
a 'climbing plant' [=a plant that attaches itself to something, such as a wall, as it grows up it]
The players 'climbed' into their uniforms [=put on their uniforms] and headed for the field.
(..) - You failed chem. - C-minus. - Well, in that case... So I'll be over around, say, like, ? - Are you crazy? My mom would not... - I'll climb through your window. She won't even know I'm there. I'm stealthy, like a ninja. You are crazy. Wait, wait, wait. Just... Okay, forget about that. (..)2016 TvShow: Stranger Things Title: Chapter One: The Vanishing of Will Byers Season: 1 Episode 1