Hmm... we definitely need a bit more team phoenix comment porn. Never done cross-dressing, but there's a first time for everything, right?
"Are you sure about this?" Harry tried to turn around and look at his bum in the mirror and wriggle his hips at the same time. The dark green lace pants cupped his crotch, lightly scratching his balls and the head of his prick with every movement.
"Trust me." Regulus Black slouched a little further down in the not very comfortable chair used in this portrait. "Would I have given you the password to my secret stash if I didn't know for sure that he'd like it?"
"Well, you were a Slytherin."
"True," Regulus grinned. "Unfortunately, I'm restricted to voyeurism these days. Now the spell to tighten the corset is..."
"Umph." Harry panted as the strings of the black lace corset tightened, pulling the pants just that bit tighter against his groin and rubbing silk against his hardened nipples. He strutted a few times in front of the mirror, enjoying the shushing that his silk stockings made with every step
He was admiring the way the shape of the corset brought attention to the curve of his bum when the door to Regulus' old room slammed open.
"Potter, what exactly is the meaning of this note," Severus snarled as he walked through the door brandishing a piece of parchment. "I don't appreciate..." his voice trailed off when he saw Harry.
"You don't appreciate?" Harry prompted, sauntering up to Severus. He stopped a breath away, posing himself slightly sideways, one hand on a hip, the other on Severus' chest.
"You..." Severus suddenly licked dry lips.
"I?"
Severus dropped the parchment and reached for Harry, sliding his hands around the taut waist and over Harry's torso, then pulling Harry against him. "You. Definitely you," he growled.
Regulus Black smirked down on them from his portrait and settled in to enjoy the show. Perhaps he didn't need to be quite so bored after all.