Yep, same here. I have to shetland geldings and they unroll their gardening hoses on a regular basis during training.

I never really noticed it as that's not really the bodypart I watch the most during training

but a couple of weeks ago when we were taking pictures of the tricks for the book, the photographer couldn't resist making the occasional dirty remark. Lots of Photoshopping done down there...

But I have discussed this phenomenon with an equine behaviour specialist, and she denied that it was a sign of relaxation and suggested that it was just accidentally taught behaviour. So when you're training the bow and your horse just let it down and you click, he thinks that that's part of the lecture and afte that always lets it hang loose when you ask that trick. Right... <_< Didn't really believe that one, as it's something I've encountered in all the horses I've trained, not just my own, but also the ones at lessons and clinics. I really think too that it's a sign of relaxation, as lowering the vulnerable bit is not something you do when you're running away from sabretooth tigers. B)