Two women who will pact for life. They will hunt down unsuspecting Sports Figures or Actors and such and initiate a three way. As the man is ready to ejaculate, one lucky lady will savor thus ejaculate in her mouth and when the man is not looking, quickly spit it into her “sperm sisters” vagina in hopes to have his baby! The unsuspecting sucker never knows how it happened but nevertheless is just another victim of the sperm sisters.
by DunnBai August 22, 2019
Women who all have a child with the same mans sperm and support each other for the sake of the children.
"We didn't know too much about each other, but now that we're sperm sisters our sons have the right to know their brothers from other mothers"
by milk9837 October 18, 2011