NICKELBACK singer CHAD KROEGER has a very unique skill:  He can put his own manhood IN HIS MOUTH.  Chad says he discovered he could do it when he was 14 . . . and a case of beer was on the line.

--Seriously . . . Chad tells "Playboy" that he was dared to do something outrageous for a case of beer . . . and that's what he came up with.

--He says, quote, "I put my own (--rhymes with STICK) in my mouth.  I was 14 and much more flexible at the time.  It was soft and required a lot of pulling.  I really wanted that case of beer."

Gives you a whole new way to look at old Chad doesn't it!!