I thought I'd start a recurring post about all the things I have learned while being the passenger riding two-up. This picture is an entirely different type of two up from what I am thinking but some of the same principles might apply. There are certain things you automatically realize you should or should not do.... and there are things you learn by doing.
I will try and write as many tips as I have learned over my years of being the passenger.... one tip at a time.
Two-Up Tip No. 1: When the bike is coming to a stop, abruptly or otherwise, learn to use your stomach muscles and upper body strength to control the speed with which your helmet goes forward (if at all) as not to strike the front rider's helmet and "ring his bell". Often times this can only be learned from experience. You will know when it occurs as if done hard and fast enough, can ring your bell as well. Please engage your stomach muscles and slightly lean back to avoid any cranial disturbances for the front rider.
"Stubbornness is also a determination. It's simply a matter of shifting from 'won't power' to 'will power'." - Peter McWilliams