The differences between BPC4 and this month's lighter-complexioned companion White Panties 7 are myriad as they are compelling.  Although the on-camera chat is about the same (i.e., pointless and boring), the black performers are relaxed and completely natural in both body and sexual activity.  The last sequence, with youthful and slender Mariah, opts for an internal pop shot.  It doesn't hinder the scene at all.