Definitely the hairbrush/bathbrush elicit a unique fascination that no other implements elicit. Of course, several other implements also elicit their own unique fascination. But this discussion thread is about the hairbrush, so here's what makes the hairbrush unique for me.
My father's carpenters' ruler and his razor strop hung on hooks in his workshop, but those implements were almost exclusively reserved for dad to utilize when very severe discipline was required. This was out back in a barn that also served as a wood shed and workshop. So, a trip to the woodshed was usually a private father/son "appointment".
The hairbrush, on the other hand, was utilized by father and mother (and even my big sister on a few occasions, when we were left at home with her in charge) in the family room, regardless of who might happen to be in the vicinity (sister, aunts & uncles, male & female cousins, grandparents, my friends, my sister's friends, friends of the family, the plumber, my sister's wedding planner, etc, etc, etc).
The protocol for the hairbrush was simple... I go upstairs to fetch the brush and return wearing only my boxers. I hand the brush to my mother or father and remove my boxers. While standing naked, hands behind my head (fingers interlaced), usually with an erection, alongside my dad or mom (before going over his or her lap), I would receive my lecture. Then I'd drape myself over his/her lap and have my bare buttocks scorched. Then corner time with my beet red ass on display for all passersby to admire.
Erections and extreme embarrassment were just an unpleasant (or pleasant, depending on one's perspective) part of the hairbrush ritual starting at about the age of 9 and continuing until my last hairbrush paddling at 16 years of age. I did receive my dad's razor strop a few times at the age of 17, and I think once at the age of 18, but no more public hairbrush discipline after the age of 16 (except from girlfriends).
The hairbrush ritual definitely brought about a unique hairbrush paddling fascination for me that continues to this day.