Ok, but to make sure you know what I am talking about:
Braum with 100 bonus armor and magic resist jumps to Braum #2 with the same
Braum #2 then gains 41 bonus armor and magic resist, making him have 141 bonus armor and magic resist
Braum #2 jumps to Braum #3, giving him 45 bonus armor and magic resist for a total of 145 bonus armor and magic resist
Braum #3 jumps to Braum #4, giving him 48 bonus armor and magic resist for a total of 148 bonus armor and magic resist
This continues on, each slowly increasing the next's bonus armor and magic resist and therefore increasing the scaling of the W's bonus armor and magic resist without having to stack the buff. They simply each get one stack of the W buff that increases their bonus armor and magic resist and therefore the bonus armor and magic resist they would give with their own W.