There is another web site almost all about this subject.
That said the idea proposed is terrible short sighted for with in a few generations white females could not exist just mixed race people with each generation becoming more and more black.
What i am proposing is different in many ways.
Yes having white females for sex purposed two weeks a month. In the third week harvesting her egg to be carried to term by a black lady having been fertilized by a white male. There be continuing white babies.
it is my understanding that it is the male that determines the sex of the baby so the male sperm could be filtered out to increase the chances of female babies.
white males would have a penectomy operation (the removal of the penis) with the balls remaining intact for breeding purposes.
Other white males would have a orchidectomy operation (the removal of the testicles) with the penis remaining intact. Now you run into an issue of reduced testosterone which leads to infertilite and in inability to get an erection. To counter act this problem monthly artifical testosterone would be used to allow these white males to be used for training the white females is sexually servicing black males. These males could also be used in keeping black female occupied while the black males were off having fun.