The others looked at me, I know for sure, with more envy than fear, and I even suspected one of them was going to tell on me to my dad. Was I doing the right thing? But there was no time for hesitation, because Anabela’s suntanned arm was already tugging at mine, her yellow down was guiding me to the sea, and her feet and mine made the pebbles crunch at the water’s edge, that was happening now and it was almost impossible to believe.
The quoted text is from the short story 'How to swim with her' by Andres Neuman. What does it mean by the sentence in bold, especially 'yellow down' in this context?