It´s a crux,if you lean a bit forward you are protect against beeing pushed but you will stumple forward if the couter pressure gets suddenly away.Also you are weak against pulling.If you lean a little bit backward you are protected against pulling but weak against beeing pushed.Sometimes I thought I would have to realise quickly if I get pushed or pulled so I can lean just in time backward or forward but that´s stupid,this cannot work.It´s about angling proper the ankles to direct the force proper to the ground.Therefore you have to gain the correct ideas within training the siu lim tao.If your taan sao is angled properly alittle bit upright and you are pressing against your partners counter pressing fook sao then the force can be deflected properly into the ground.When you are counter pressing with your fook sao against your partners taan sao your forearm has to be directed a little bit upward and your elbow has to point to the ground.You have to press your elbow slightly in direction to the ground.The rest is about hip control.Sorry it´s hard to explain in words but I hope you understand what I mean.
Ralf