You want to know "the best way to crash a bike"? Maybe look at some Jackass type videos on youtube. I think all my crashes while cycling were unforeseen, never a serious one with major injury. At least half of them were with no time to react in any way. But. I do see your point. I was a wrestler, and through practice and experience, learned how to fall, but, only through experience does one gain mind and muscle memory to stay loose and not panic. I do not know how I could practice crashing and falling while riding a bicycle. Awareness, expecting the unexpected, equipment in top operating condition, are keys to preventing crashes and falls, to begin with.