There seems to be some variations of it, but I am talking about:
--1---
--1---
--2---
--3---
--X---
--X---
So, I place the tip of 1st finger on 1st and 2nd string. Using maximum force and contraponing on the board with my thumb, I can just make both strings sound. But then the next string, 2nd finger - it's impossible! I can't put that much force on all strings, or at least without touching 2nd string with 2nd finger.
Any hints to that? :-)