Regulus Black

Regulus wrote what he wants to say to Sirius ages ago, but hasn't been able to bring himself to send it. But if he doesn't now, he might as well not have bothered.

Before lunch, he heads up to the owlery. If he sends this with Phineas, that's a guarantee Sirius won't even take the letter. He gives it to one of the smaller school owls, adding, "Just... take it to his dorm. You don't have to wait for him, either."

The last thing he wants is to put Sirius through dealing with this in the middle of the great hall.

Later that night, in the privacy of his own room, he writes another quick note (Narcissa - We should talk, over hols. I've a project you might be interested in.) and ties it to Phineas. "You know where to find her."

It's as close as he wants to get to talking about his plans in any form that can be traced, but he wants her to have this in mind, between the formal functions of the season.