[It's very rude to talk over other people - it isn't something Sebastian makes a habit of doing unless to prove a point. Certainly not for some bad language when there is no young master around to hear it.
But maybe the clink of the cup of tea Sebastian sets down on the counter in front of Lucifer is audible enough to muffle certain words somewhat.]
Chamomile is good for frayed nerves, [he explains, very innocently. Calm down, you.]