SNM:
Another archetype I like, sort of the opposite of the aforementioned.
A devious, mischievous spanker, usually female. Puts on a veneer of the responsible disciplinarian while conspiring to get the spankee in trouble, either over her own lap or someone else's where she can watch. She's (usually) more mischievous than actually cruel, and doesn't mean any real harm, though you may have trouble convincing the victim of that.
For a change of pace from my usual mature, responsible, self-confident spankmistresses, I occasionally like to portray a feminine spanker who has subconscious reasons for desiring to corporally correct her victim very soundly and quite often, although she's not consciously aware of them herself. (For example, I once wrote a brief account of a preteen girl being babysat by a teenager, who reminded the babysitter of her little sister, whom she resented. The teenager had no ability to discipline her own sister but did have spanking authority over the preteen she was babysitting, who predictably ended up getting plenty of bare-bottomed wallopings from her.)
In a such a case, the punitive female considers herself to be merely a "strict disciplinarian," and may never overtly realize that she has repeatedly spanked the person she has disciplinary authority over unfairly, in the sense of punishing him/her for very minor, trivial offenses, and/or creating situations in which it's almost impossible for him/her to behave in a supposedly 'acceptable' manner to avoid chastisement.
(In the example I gave above, the truly devilish aspect was that the preteen girl's mother and aunt were inflexibly committed to a policy of "Spanked by the babysitter means spanked more severely by one of us once we get home, in front of her." Yikes!!)

--C.K.