ok, ok, ok... so today I was flying left seat in an OH-58D. Crossing through the Rocky Mountains. DA was around 13000. VNE was charted around 87. My right seat pilot was flying at the time, and was trying to catch up to the flight. During an acceleration the aircraft began to "shudder" and a mushing feeling was felt. it was followed by the nose trying to pitch up, and his first reaction was to apply forward cyclic due to the nose pitching up... as the forward cyclic was applied the vibrations continued to increase and the aircraft rolled RIGHT... I have read this whole thread a few times previous to today, and I also know for a fact that it rolled right. the pitching up was at max 5 degrees becuz he applied forward cyclic. The roll was 15 to 20 degrees... RIGHT. I have the event on video from a gopro. I will also go on to say that none of this pitching or rolling was violent, and the vibes were not anything severe. we have been trying to figure out all day what is causing the right roll, now that we have seen it first hand... could it be due to improper control inputs( forward cyclic) which increases blade angle at approximately 9o'clock? im assuming the text books only cover the situation from the perspective of the pilot doing the right thing and pulling aft cyclic to slow down/ doing nothing at all? im intrigued, to say the least. I am a 2000 hour CFII in RW, and also have a good bit of time FW. I know what I saw and felt. Now I NEED to know why.