In the early 1940s, when most of our schoolmasters vanished into the Armed Forces, the all boys school which I graced with my attendance enlisted a number of young ladies as teachers, and one of these was a particularly attractive and rather young gym teacher. She always dressed entirely satisfactorily for the part, and always taught by example, so that every exercise we were to perform she performed first as we sat cross-legged in a circle on the floor around her.
The sight of exquisite naked lower female limbs and, as her very short gym skirt floated upwards, her tightly clad crotch and buttocks, as she demonstrated a somersault over the vaulting horse, or even better as she climbed steadily up a 20 ft. rope was sufficient to deflect the attention of many a 12 year old from his studies in the next maths or latin lesson.
Oh, to be young again!