Whilst growing up, bro and sis had to share a bed. Then he moved out and finally had a bed of his own! One day, his parents decided to take a holiday and rather than leave their daughter home alone, requested she stay at her brother's apartment. No complaints from her! She'd missed her big bro...
Sure, hed have a futon set up for her and sure, she may have started the night there...but, drawn to old habits and her brother's warmth, she'd soon be snuggled into him. Of course, she was a lot more..developed than last time the two had snuggled like this!