We had a busty, but appropriately clad woman demonstrate how she carried with her shirt tucked over her gun. She did the draw exactly correct. With her off hand, she reached down and grabbed, solidly, a handful of shirt and in one clean and forceful jerk, untucked the shirt, uncovered the gun, which she then drew with her strong hand quite efficiently. Only, somewhere in her training did she not learn to let go of the shirt. While there was nothing to see but a very supportive bright white bra with frilly trim, it stymied several of us at least long enough to realize that if she had come in our place of business and pulled that stunt, we would have missed the gun until it was out and pointed at us. Talk about a distraction move!
Her gun did not actually ride completely covered by mammary tissue, but the back of the slide, hammer, and grip certainly were.
To this day, I do not personally think that a two handed draw where the off-hand must perform an action to make the draw successful is a very efficient way to draw. Such activities complicate the process and so more things can go wrong. However, the visual distraction does add a new feature. Keep in mind that a similar effect can be attained by an obese fish belly white guy doing the same draw, only instead of keen interest, the image of the motion rippling fish belly white fat gut will offer the distraction of repulsion. People will be inclined to turn away and never see the gun. Also keep in mind that such guys face the same corrsion problems noted above if carrying in a similar manner.