Hi! So this is my first ever Sizzy piece! This got away from me, but it was so cute and fun to write. I really enjoyed writing this. I hope you all like it as much as I do.

Disclaimer: I don't own anything at all associated with Shadowhunters or the books it comes from. I just like to play around with the characters at times.

tumblr request from sizzymontgomery - could you do a sizzy + "Is that my shirt?" fic? that would be lovely

"Is that my shirt?" Simon asks from his position leaning against the door frame.

Isabelle smiles at him in the mirror. "It is." She spins around to show him the front of her newest masterpiece, in which she's turned the overall shirt into a halter top with the front as a crop top. "Do you like what I've done with it?"

"Have you been watching clothes hack videos on YouTube again?" Simon asks, squinting his eyes.

She shrugs, grinning. "I had to after last night's escapades ended with my shirt to be torn up."

"I've suggested moving in together for months now," Simon pointed out, pushing away from the door frame and walking further into the room.

Isabelle laughs. "And I've told you time and time again, you do not have a big enough closest for me to move in."

"We could make one," he offers, walking up to her and wrapping his arms around her waist.

"Are you going to kick your mom out of her own place so I can make her room into a walk in closest?"

"No, of course not. That'd be absurd."

"My point exactly." Isabelle turns back to admire her creation in the mirror. "You could always move into the institute with me."

Simon laughs uneasily. "What so a Shadowhunter that isn't happy about our relationship can sneak in and stake me in my sleep? No thanks."

"I would never let that happen."

"I love you, Izzy, but you sleep like a log... I wouldn't trust you to wake up in time."

Isabelle widens her eyes and lets her jaw go slack as she feigns insult. "How insulting. I'll remember that when you need me to save you next time."

"Or even better... I can make up for offending you," Simon suggests, reaching around her to begin untying his... Izzy's shirt.

"It's possible that I can be persuaded to forgive you," Isabelle muses, turning in his embrace so she's facing him; in the process causing her shirt to unwind open.

Simon glances down at Izzy's now half naked form and then makes eye contact with her. "You should do DIY hacks on my shirts more often."

"Duly noted," she responds before closing the gap between them.