D4L are a five piece rap group from Atlanta who may only have only been around for a while, but have already formed a proper hip-hop feud with fellow rappers Dem Franchise Boyz and reached number one in the US last year with this record, Laffy Taffy.
Laffy Taffy isn't actually a particularly jocular Welsh person, but appears to be slang for a woman's posterior ("shake that laffy taffy, girl shake that laffy taffy" as the chorus helpfully tells us). This phrase is shouted over one of the most simplistic beats you'll ever hear, which appears to have been composed by simply switching on a Casio keyboard and pressing a random setting.
It's moronic, crude, irritating and doesn't appear to have any redeeming qualities whatsoever. You can't even particularly dance to it, which is surely at least one prerequisite for a dance record. Poor in the extreme, but that probably won't stop it repeating its US success over here - sadly, it'll probably be blaring from someone's mobile phone as you're reading this.