How do speak the barber language so I can finally get a good hair cut?

[Darrenjonathan]

Hello Men

First time posting so very excited to be here.
The problem I have is when asking for a haircut I they don't seem to understand that u don't want my head rounded.

I like to have a square haircut to shape my head. As in I like a bit of lenght on my sides and the top of my head to be longer and to be the same length for the most part as the back.

So my hair type is between wavy and coild, I have nice curls that come out with a bit of lenght. But for some reason they think I need to shape it as if I had straight hair.

Yesterday I had a bad haircut. He took to much off the sides and the even took lenght off the top to much at the back. Barbers seem to say I'll take just this much off (1cm or less) but them keep taking that off so they actually take 2-3cm off.

They don't seem to understand what square shape means.
I have seen posts about a two step haircut.

Can anyone help me in learning how to tell them what I want, without seeming like an derriere but still getting the haircut I want.