Originally Posted by 2manybikes

It sounds like you had a wind that was slighty towards the rear or straight form the side. What you did is just like a sailboat trimming the sails to catch more wind. If you got your back more at a right angle to the wind you catch more wind. If the wind is fast enough of course it will give you a push. You are a sail.

If the wind is straight sideways and your back directs the wind back at an angle it can push you forward.
Anyone owning a sailboat would think this is not complicated. One time I had a tailwind from off my rear quarter and I had on my windbreaker, unzipped. I sat up held the jacket open with both hands and it helped a little, when I twisted my body and got the "sails" (jacket) to the right angle my jacket caught a lot of wind and I accelerated for almost a block.