If you're off by a decade, this sounds like "The Curse of the Mohndoro Nkabele or The Revenge of Stanley G. Weinbaum" (1978) by Eric Norden, published as "The Curse of the Mohndoro Nkabele" in The Magazine of Fantasy and Science Fiction, September 1980.
The story takes the form of correspondence between the editor, Edward L. Ferman, of Fantasy and Science Fiction and a would-be author O. T. Nkabele.
There is a reference to aliens and well-endowed women:
In a different vein, but equally jarring, the Gargons of Ganymede you depict in URSULA OF URANUS are, so far as I can gather, no more than oversized purple lobsters, and it's unlikely they would have the capability, much less the desire, to ravish Ursula and her friends. (Avoid euphemism as well as anachronism, as in "Ursula's mammoth mammary protuberances heaved in horror as she watched the slimy giant crustacean approach....")
Mr. Nkabele does in fact change the lobsters to giant gerbils:
Thus, I am enclosing a revised version of SLIME SLAVES OF G'HARN, tailored to meet your objection about the sexual preferences of the Gargons of Ganymede. They are no longer giant crustaceans but giant gerbils which, being mammalian, should have no difficulty consummating their lustful desires for Ursula.
There are definite suggestions that there is some kind of evil magic being worked on the editors (other publications are subsequently targeted as well):
Ellison rebuffed the African too, and look what happened to him. Christ, I may be next! The drums are getting louder every day, and I've developed sharp, stabbing pains in my chest and joints. This morning I found my parakeet dead in his cage, his little neck snapped like a twig. And the cage was locked, Isaac, I had the only key. I know you're a confirmed rationalist but I swear to you, I am being hexed! Or voodooed, or hoodooed or whatever the right African name for it is.
Mr. Nkabele steadfastly refuses to admit there's anything magical going on, but does admit to some familiarity with magic:
I have received your wire and am most sympathetic to your plight, although I cannot countenance the idea that multi, or witch-power, is at the root of your difficulties. Nevertheless, inasmuch as your welfare and happiness are so important to me, I have swallowed my doubts and performed certain uchawi rituals of cleansing or, in Western parlance, exorcism, that were handed down to me by my uncle, the Mganga of our people. If a vindictive mhondoro is indeed pursuing you, he is now banished to the Eternal Night from whence he came.
I have to say that his disclaimer of any attempt to do magic is somewhat undermined by his insistence on finding the barber of anyone who he wishes to deal with, viz:
P.S. I'm enclosing a list of the members of Science Fiction Writers of America, and most of their addresses. Under separate cover I've sent you a convention folio which has many of the photographs of individual writers you requested. They should be voting on the Nebula Awards in mid-April. I'm afraid I don't know where any of them have their hair cut, but I'm sure you'll find out.