When I was younger and didn't really know how to masturbate, I would rub my penis against my leg until I came. It'd always always be against my left leg. Well after about two years of doing this every night (and oftentimes during the day, too), I noticed that my penis would lean slightly toward my left leg while erect. I tried to correct this by rubbing it against my right leg. It helped mostly, but I'm still a bit leaning. Now I masturbate the real way usually, but I just think it's funny.
So if you ever end up having sex with a guy whose penis leans to the left, it might be me!