A comment from Nonce provides a nuanced addition to the principles I set out in the first post on this topic. I paraphrase him.
While the Mistress remains completely within the bounds of self control, a momentary, animal like, intensely aggressive and hostile, concentrating facial expression appears, particularly when she is close to orgasm.
I have seen this expression and demeanour on Dommes I have collaborated with. It is 100% intensity and spiteful focus to cause discomfort and by so doing gain their own fulfilment. It is erotic and, for the submissive, very frightening.
On a different note, this sequence of posts could not be complete without a contribution from the wonderful Mistress Margret.
Sometimes when I am halfway through a punishment session with the cane I will stop and make a phone call to a friend or a family member.
I will laugh and chat away while sometimes pinching the welts on his sore bottom or just sit where he can see me and completely ignore him.
sissy has told me he finds that when I do this laughing talking and planning shopping trips and whatever is hard to endure and knowing that there is more strokes of the cane to come makes it even worse and just prolongs the punishment session.