I didn't say much after she said no and I told her that was fine, that I'd be fine with just paying her straight up myself. She was very angry and all I could do was apologize for offending her, which was ignored. At the point where she stated that she didn't care whether I wanted it or not, I replied with "Whatever dude, we'll figure it out later" (not meant in a rude or snarky way at all, though I can see where it could be misconstrued as such) and left the stream so she could work on her current commission in peace.

As Carrot stated somewhere else in here, Sin and I were fairly good friends for a long while preceding this situation, so I was rather taken aback by how she responded to my idle inquiry. I definitely didn't mean to overstep any boundaries, and I regret having done so publicly; I didn't think very hard about it before doing it, since we'd often just chatted about commission ideas and options in streams beforehand. That is fully my responsibility, and though I believe her reaction was a little over the top, I was in the wrong in provoking that situation and should have asked her about it privately.