Ok well it turns out it's not a bug in the game code but instead just an error in how the "pulled" version of this outfit's bottom was made.
Here's why this causes a problem:
Each position has a value in its XML file that tells the sim whether there is penetration or not, and if so what kind. If the pose calls for bottom penetration then the sim shows the "pulled" version of the outfit (in other words, it uses the "z_" bottom texture). If there's oral or no penetration then the sim doesn't show the "pulled" version and shows the regular bottom texture.
In the oral positions the sim isn't calling on the pulled texture, so it's showing the outfit as it is in regular mode. In the other poses it is using the pulled bottom texture.
If you compare the regular bottom texture with the modified "pulled" version in Photoshop or GIMP, you'll see that on the regular one the breasts are covered, but on the pulled one they aren't. So all that needs to be done is for oncesailor to modify the regular bottom texture (Black-Fishnet_t-b.png) to also have the exposed breasts, and then everything will work as it should.
I hope that makes sense. Just ask if it's not clear.
Oh, and I didn't mention this yet, but pronzilla you did an awesome job with this outfit, it looks great. And oncesailor's mod is really well done too. Good job you guys.
