Great job with your sexy slut! She seems to be very obedient.
Why not reward her more with more Black only gangbangs or better yet
Build her a breeding board and set up some breeding sessions.
My wife loved her breeding sessions, that sometimes lasted for hours, but we found that after about 5 or 6 young bulls came in her, the cum would start to be pumped out by the next cocks. The fix for that was to have a catch bowl under her pussy and after all the men were satisfied, I would suck up the cum with a baster and push it to the hilt in her upturned pussy, fill her deeply, then cap with a buttplug held in firmly with a tight pair of panties and carry her to bed with pillows holding her ass up high and then put on her leg restraints to hold her firmly in that position for the night.
Of coarse the result was when she decided to go Black only, She modified the breeding board with a hole for my cock and balls and that became my bed securely bound until her lover(s) had their next morning fuck. then She would release me for the days chores. after a while I really got to enjoy sleeping that way lol.