Hmm I always wonder what sperm do if they're all banked up over a few days. Do the first ones get in first? Do they all hang out in a gated area together then all make a break for it when egg appears? The big questions!
It's all very interesting isn't it? I watched as suggested - on you tube "the great sperm race documentary" quite an interesting watch really put things into perspective of how miraculous the process is...