Cheerleaders commission

This work makes great use of its own setup.
One of the biggest problems with ball gags in visual pornography is that they tend to render characters unexpressive, but this picture works around that nicely by using the girls' eyes and posture to convey what they're thinking. It's another good touch that, from left to right, each of the black girls appears to be in a more advanced state of sexual submission.
More generally, these characters are drawn economically; there are no more lines than there need to be. A simpler face is always more expressive, and a more expressive face is always sexier.
Finally, the objects on the floor do a good job of establishing context, which is another underrated ingredient to good pornography. They indicate (to me, anyway) that this scene was consensual only well after it began.
Overall, it's a very well thought-out piece with hotness packed into every little subtlety.