I have some experience with martinets or at least small floggers which I believe meet the definition.
Many moons ago I decided to make these after acquiring 2 very substantial lengths of leather bootlace material . One approx 4mm square and a lighter one around 2mm square . 10 or 12 appropriate lengths would be cut from these and then attached to a handle made from a 7inch length of 1 inch broomstick. The thongs protruded about 7inches from the handle. To give a professional look a length of rope was coiled loosely around the handle which was then over taped with black LX tape. This gave the handle an interesting curled look.

I donated some of these to professional ladies with whom I was socially acquainted at the time and understand they were put to good use.
For reasons of tradition I usually preferred the hand., slipper (usually bedroom variety) and cane in the classroom but occasionally did diversify to the martinet , usually in one to one situations. Due to it’s relatively short length it is quite good to use in the OTK position. The heavier thong version was definitely the more painful and if applied with any vigor would produce a sharp intake of breath or usually something a lot more vocal from the toughest young ladies.

However ,applied more gently it can be an excellent warming up implement and when lightly applied some ladies enjoyed the delicate sting perhaps a bit more than they should .have . Of course I was much younger and in much better physical condition in those days.

At my elementary school, there were no male teachers or admins.   At my middle school, there were 3 male teachers and one male VP.   Most of the pupils getting spanked were male and almost all of the adults were female, so, of course it was normally a female spanking a male.  I only got one at school and it was from a 50 year old female principal.  And the witness was female.   It was not something I thought about at the time, it was just a hard spanking and super embarrassing.  But that not just because a female did it but all the females (including peers) who quickly learned it had happened.   After 10 years or so, I did start to find the presence of the witness back then to have been interesting.  But, no, the spanker was almost as old as my grandmother that day.   So, her gender was not part of my thoughts.