The Collaborative International Dictionary
Birch \Birch\, v. t. [imp. & p. p. Birched (b[~e]rcht); p. pr. & vb. n. Birching.] To whip with a birch rod or twig; to flog.
Wiktionary
n. A beating with a birch. vb. (present participle of birch English)
Wikipedia
Birching is a corporal punishment with a birch rod, typically applied to the recipient's bare buttocks, although occasionally to the back and/or shoulders.
Usage examples of "birching".
The skin was broken nowhere, but here and there, particularly at sensitive places near the shadowy crease which separated the globes one could see dark splotches and stigmata as evidences that the birching had been rather severe.
She failed by five, and was sentenced to a birthday birching which Maude herself applied whilst Alice was, still blind folded, undressed down to camisole and elegant black silk hose with purple rosette garters and tied with her arms in cross and her thighs widely yawned apart in the middle of the room, cords fixing to wrists and ankles being fixed at their other ends in turn to hooks set into the cellar wall.
Alice had sentenced her to a sound birching on the bare, to smarten up this diffident pupil.
You deserve a sound birching, Miss Ashton, and you are going to receive it.
Her name is Charlene Davidson, and she has been wanting a sound birching for quite some time now.
Her violent contortions over the tabouret, needless to say, showed off the most secret parts of her nubile young body in the most lascivious way, and Maude righteously exhorted Charlene to take her birching humbly and not be such an indecent minx, advice which poor Charlene could not have heeded at this point, much less count off the strokes.
As for you, my girl, if I hear from either of my nieces that you have been indiscreet enough to repeat a word of what has been said here in this room tonight, you shall repent it over the birching horse before the entire school.
Beetlebacks rape our women, and the courts acquit them, often ordering birchings for any woman who complains.