Your hair was getting longer and less manageable with each passing week. A haircut was not an option simply because you didn't have time. Or were pretending to not have time, but that's not the point.

The point is that Regulus was tasked (or burdened) with helping you straighten your hair. You realised you haven't straightened it in years, so now here you two were: standing in the bathroom of your apartment. Regulus was looking at you like you were committing a crime right in front of him.

"You do know this is just going to make you look like an old broomstick?" Regulus asked calmly. At the moment, he was holding a comb and a spray bottle with heat protective liquid in it. His remarks have been nothing but snarky and sarcastic for the last twenty minutes.