yea, you're right, they always use eachothers stuff. i hate rap. and why the heck do they curse so much? they'll make a whole "song" out of two words. even though rock songs curse too, DEF. not nearly as much. ugh, i HATE rap. (except for the few songs i like, haha)
cursing in rap nowadays is more to fill syllables than to express seriousness or a give a strong vibe. it's so dumb. SOME rappers can write really smart stuff and stay light on the cursing, but some dumb rappers use the cursing as a crutch.