Draco had put off this moment as long as possible. He'd gone downstairs for a glass of water, taken an inordinate amount of time finding his pajamas in his trunk, and done every grooming task he could think of in the bathroom. (He hadn't exactly needed to trim his nose hair or tweeze his eyebrows, but it never hurt to be well-kempt, right?) But now the moment had finally come and he was crossing the threshold of Dudley's room.
Things could have been worse. While Dudley only had one bed in his room, it was a gigantic king-size that could have comfortably accommodated three or four normal-sized people. Which meant that even Dudley and Draco could sleep in it without touching. No, that part was probably going to be ok. What Draco was really afraid of was that Dudley was going to want to talk to him about stupid things all night long.
For some reason, Dudley felt compelled to pour out his heart whenever he and Draco were alone together. The first time, down in the Chamber of Secrets, hadn't actually been so bad. That was how they had discovered there mutual hatred of Potter, after all. But now that Draco knew the Dursleys a little better, he knew how many hot-button issues there were in the household. And he desperately didn't want to hear the gory details, especially not as processed through a small mind like that of Dudley's.
Draco finally entered the room and breathed a sigh of relief as he saw that Dudley was already asleep. Maybe he'd be able to get through the night without incident after all.
Unfortunately, he soon realized that was not to be. Dudley had often been compared to a baby whale, and unfortunately that label fit his sleeping style as well, which involved a lot of energetic flopping around the bed. It struck Draco as funny that Dudley should be so much more athletic in his sleep than he was during his waking hours. He supposed all the potential energy in Dudley's great bulk had to be expressed some way.
At any rate, it was obvious that sharing a bed with "Big D" was not an option. Draco briefly considered sleeping on the floor, but there was almost no floor space that wasn't taken up by all Dudley's many possessions and Draco's trunk. He even pondered sleeping inside the trunk, but that sounded way too vampiric for his taste. He finally realized that there was a perfectly good sofa in the living room and that he might as well sleep there.
Unfortunately, it seemed that Potter had come to the same realization, as his sleeping form was sprawled over the sofa when Draco arrived downstairs, and no amount of shaking would rouse him. Draco racked his brain for alternatives, and finally came to the conclusion that there was only one.
And thus it was that Draco Malfoy, heir to Malfoy Manor and possessor of proud Slytherin blood, found himself passing a mostly sleepless night on a small, uncomfortable cot in the cupboard under the stairs.