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.
(..) To ask you... to open your gates, my lord... so my son and his bannermen may cross the Trident and be on their way. - Why should I let him? - If you could climb your own battlements, you would see that he has men outside your walls. They'll be corpses when Tywin Lannister gets here. (..)2011 TvShow: Game of Thrones Title: Baelor Season: 1 Episode 9