markuk:
What do you think is the best way to write a counting punishment (usually caning for my stories) without it becoming too repetitive and boring?
There's always a danger of repetitiveness in describing an implement-based punishment of several strokes/swats, even when counting isn't involved. Having conveyed a couple of times the sound of a stroke/swat, its effect on the bottom, and the spankee's physical and verbal responses, it's hard to avoid sameness thereafter - hence, as CrimsonKidCK says, the need to 'skip ahead'.
Making the spankee count their strokes (forcing them to speak) has the benefit of revealing, through their voice, the degree of pain they're in. I, for one, find this quite erotic. Perhaps you could use description of the counting, then, as a way of conveying the spankee's gradual descent from brave forbearance at the first to agonised croaking at the sixth. This might work best if it's the spanker's perspective that is foregrounded in the narrative (assuming it's third-person).
The cane swished and struck. She gasped and bent at the knees before straightening up obediently.
"One, sir," she announced boldly to the carpet, a breathiness in her voice the only admission of discomfort.
He laid on the second, enjoying the suppressed squeak that followed hotfoot on the sound of stick on soft flesh. After a panting pause, her voice quavered as she acknowledged, "Two, sir," through gritted teeth.
At the third, she squealed, the insides of her knees rubbing as she wriggled her bottom. Stilling herself, she panted hard before a decidedly self-piteous "Three, sir," emerged groaning from her up-turned head.
etc.