[Ahh. What an odd - and thoroughly disagreeable - feeling, to suddenly be hit with the memory of this miserable adventure, the excruciating pain of that injury... all while the wound is still fresh enough to have barely healed. The satisfaction of ripping all those soft, rotting bodies to pieces at first, and later the desperate urgency of that same action. The humiliation of his pathetic state... and despite that, the concurrent thrill of all that excitement and urgency and novelty.
Sebastian watches all of this play out, not looking at Lucifer but eventually addressing him anyway:]
You see why I ask you not to thoughtlessly do things like that? Somehow, I keep hoping that you will think ahead just once... In any other circumstance [ONE THAT WEREN'T CAUSED BY YOU] I would apologise for this unnecessary display, but...
[But now Lucifer will just have to deal with witnessing Sebastian's private memories. ...If it isn't obvious, this is a very roundabout way of expressing displeasure that Lucifer keeps seeing him in these vulnerable states.]