You may move in shiftly, cover a Boxer and strike him

After handling a Boxer's jabs and crosses, course participants proceed to handle hooks and undercuts. Intercepting with "Por Pai Sau" or "Flank-Breaking Hand" is an effective counter against hooks. But if the hooks come in small arcs, you may cover them as in the case of crosses.

Undercuts are powerful attacks. Blocking them, as many people do, is not a good response. An effective counter is to follow their momentum and use "Tai Wu Sau" or "Raise Pot Hand" to grip the opponent’s arm, then fell him with a Cockerel Kick, or cover him and strike his ribs.

Of course if you are ready you don't have to wait for a Boxer to initiate, you may make the first move. Move in shiftly, taking care to cover him adequately so that he cannot jab you as you move in, and strike him.