Partial answer. I assume the rap portion you're referring to is part:
Please, no, keep back, I can't take it / You're drivin' me wild / I
might not make it / You got me lookin' like buckwheat, oh / Hair
pulled every which way but me / Far from Medusa, but your looks are
deadly / You're walkin' soft, still I hear the medley / Uh, shiver my
timberland boots, cramped my style / She drives me wild (source)
As for why it's not been officially released... I have not been able to find any definitive information. My guess (based only off of personal observations) is that it's due to the Rap being performed by a different artist (Aquil Davidson), and publishing issues related to that.