Missed clipping in my left shoe after mounting and took a slow motion fall to port. After an initial evaluation determined no broken bones resumed my start and was shocked to find things were no longer arranged appropriately as there seemed to have occurred a dislocation of sorts in my crotch area. Fortunately when I dismounted and reassessed the situation I saw that my seat had rotated around 15 degrees to starboard. Phew! That was a relief! First tumble in two years. That let's me be worry-free for a fair amount of future riding.