in beginning what did Ecki mean when he said he would reveal...

In the beginning what did Ecki mean when he said in the locker room that he would reveal something to his best mate's girlfriend? He also said that he would show her what a real man was. I got the impression that Ecki and his friend were having sex currently or recently but then the rest of the film, not only didn't follow through on that idea, but seemed to refute it.

Perhaps something was cut out or there was a translation problem with the subtitles?