If Draco had bee more sober he would have panicked and pulled away from that friendly arm. Instead he found himself leaning into it, enjoying the warmth and missing it when it was gone. It was unexpected, and Draco was already thinking about what he could say to get Potter to do it again.
His brain had just managed to catch up to him as Harry mentioned buying chocolates, and then moved on to one night stands.
"Well, I've got a few to pick from. Lupin, Your father, Professor Snape, Weasley." He looked at Potter out of the corner of his eye. "You. Trouble is everyone seems to have an incurable case of the not-gays. It's tragic, really."
He hesitated for a moment, then turned so he was looking right at Harry. If you couldn't be brave while drunk on the astronomy tower then when could you?
"Alright. So, Potter, have you been staring at my arse?"