对着墙往里一点点推啊
http://wapbaike.baidu.com/view/3532927.htm?fr=aladdin&ref=wise&ssid=0&from=844b&uid=0&pu=sz@1325_1325,ta@middle____&bd_page_type=1&baiduid=E8968EDB0B7502BBB6E7B51FA328EA21&tj=Xv_2_0_10_title
先压腿
