It's more bragging and trying to get validation from your boys but I can see where low self-esteem would tie into it. Publically outing girls you've done shit with is a very good way to get yourself blacklisted lolAbsolutely right. It is low self-esteem, these promiscuous boys also have low self-esteem, because which normal, confident male, would feel the need to tell his 'boys' that he slept around.
It is apparent that they get their identity and self-worth from other promiscuous men, instead of from within themselves.
That's why they pass around texts, nudes and sex tapes.