you need to do 100 hits with your hands!! and if you do it with something else, the counter will reset and you need to defeat the boss with a 100 hit streak, the easiest way to do this is by using the "anime" character, pumping up his "karate kick" to the maximum. here is the video after which I got the achievement
https://youtu.be/GEpxZWMiXfQ?si=h59VWQ4Hh_GbEDpT
(unfortunately, my friend with his crooked hands turned off the recording a second before getting the achievements, here is the link to his profile: https://steamproxy.net/profiles/76561198448147025 as proof you can see that he completed this achievement in Stick It to the Stickman and that he is my friend)
it's much easier to do this achievement in a new save once you get "weeb"

Work out alot on the three mats in the gym upgrade room

The secret character for dayshift helps

Fazer um novo sabe deixa bem fácil

Weeb

Recomendo vc fazer um outro save e pegar o week, sempre que vc precisar escolher uma nova habilidade pega o golpe cortante e upgrada até o máximo e usa no CEO, mas toma cuidado pra não derrubar ele

ok thanks

use weeb and upgrade karate chop