You tackle a opponant in rugby when he or she has the ball...
watch this game and you will see how it works... Its much easier to watch than read... England beating NZ last year.
When one of the opposing 15 players runs close by with the ball, you launch yourself at then grabbing their legs just below the knees so they can't move,this will bring down some lighter players however,running towards them will build your momentum enabling you to stop a more "chuncky'er" foe... Often the opposing player will try do duck so be careful or it might class as i high tackle which is illegal and could get you sinbined( sent off)
