Don't buy a toy - ride your bike! Get yourself up to a good rate of knots (downhill if possible) and then go full right rudder on the handle bars, without leaning over. Whilst dusting yourself off and / or phoning for an ambulance consider the following. The turn you initiated by moving the handle bars was, in effect transmitted to the wheel circumference at the most rearward point of the wheel. You must think this through and fully understand that point. Move that force through 90 deg the direction of rotation and you have the reason that you are now bleeding. Now think the theory through by considering what happens when you lean. Too many words - **** I failed.