Well, without proper details, it's difficult to determine what this 'cock sucking challenge story' entails. It could be a prank story, or perhaps some sort of made - up dare among friends that got turned into a story. But again, this is all speculation without more information.
I'm not sure specifically as this seems like a rather strange and unheard - of story title. It could potentially be about some wild experiences on a tour bus involving rockstars, but without more context it's hard to say.