下手

He who strikes first prevails; he who strikes late fails. / To take the initiative is to gain the upper hand. / The best defence is offence.

I can never have the heart/bring myself to impose corporal punishment on the students.

He is too soft-hearted to get it done.

In a war, can you afford not to be cruel?

attack in advance

not know where to start

wait for the opportunity to strike; play a waiting game

be eager to set to sth

strike out at sb

strike when the opportunity arises; not strike until the time is ripe

attack sb in the back

choose a proper opportunity to start

sit on the right of the boss