Forbidden...

"Oh my Godric Y/N!" Antheia squealed clutching your arm as you both walked back to your desks.

"Sirius! Sirius Black! Here for a whole year! How lucky are we?"

"Yeah heh heh..." you answered faintly. "So lucky..."

"Bags I get the first assignment with him!" Antheia gleamed.

"Yeah sure, go ahead"
"I will! I'll just pop down and see if he has one now." You watched Antheia give a big wink then gamely sway her hips back and forth on route back to the Auror Office.

Ok so you need to rethink things:
-You will be seeing Sirius a lot it seems
-Antheia is bound to find out
-It'll be worse coming from a source other than yourself
-You need to tell her ASAP
-Oh Christ she is going to HATE you
-You deserve it ~your conscience clearly disapproved.

You were so lost in your thoughts you didn't notice Antheia return.
"Y/N, Sirius wants you." she called loudly making you jump.
"WHAT? NO HE DOESN'T!" You squealed turning quickly in your chair.
"Frowning at you quizzically Antheia corrected herself "no, he wants to see you. He said send him a message when you are free and he'll come up."

Oh crap.
"Oh, I'll just go and see him now, no point wasting an memo and I could use the walk." you finished lamely.

You hurried off to the Aurors' floor before Sirius made his way up to your office, Antheia calling out to you as you left: "...Just don't tell him I have a crush on him, promise?"
"Sure."
Bollocks.

There goes your main reason for getting Sirius to stay quiet about the fact you both shagged. On second thought, Sirius didn't seem like the type to talk – he had a whole mysterious vibe going on but in a governmental office – things got around. You would just have to tell Antheia as soon as you worked up the nerve.

Yes, you collected yourself as you strode down the hallway. It was clear what you needed to do:

-See what Sirius wanted.
-Tell Antheia
-Spend the rest of the year trying to make it up to her.

Sirius was standing on the second floor chatting to Moody and a bunch of Aurors when you appeared out of the elevator.

Once he spotted you he excused himself and walked towards you, devastating smile appearing on his features.
"Y/N! Hi, do you have a minute?" He gestured to a door immediate left of the elevator.
"Yes, Antheia said you wanted to see me?" He followed you into what you assumed was his new office judging by the lack of furniture and a box a new files sitting on his desk waiting to be unpacked.

"I'd offer you a seat but they haven't furnished my office yet!" Was Sirius nervous? You smiled, inclining your head encouraging him to keep talking.

"I wanted to give you this," he moved towards the box on his desk and pulled your black cloak from it.
"My coat!"
"Yes, you left it at my house after the Christmas party. I didn't get a chance to get your address before you left otherwise I would have returned it earlier."

"My address?"
"Yes."
"You know where I work though, you could have owled it here?"
"I could have." Sirius hummed. "I wasn't sure if you would be here and wanted to have to explain to the mail room why your coat was at my house?"
"Yup. Good point" you concurred.
"Also," he said hurriedly noticing you reaching for the door. "I wanted your address as I didn't know if I would see you again. The Ministry didn't offer me the contract until just before New Year."
"You wanted to see me again?" This threw you. Sirius Black wanted to see you.
"Yes I do." The tense change in his sentence was not lost on you.
Sensing your hesitation but concluding the wrong reasoning he hastily added: "that is of course if you wanted to see me. No pressure, I know it might seem odd now since we still work together.
"No, I mean yes it is...but that's not why...I mean I'd like to...ah I'm not..."