Get/keep somebody onside phrase
To coax someone to back you up or to keep on backing you up.
John is the strongest in my school. If we can get him onside, we will win the fight.
Getting John onside boosts the morale of our team.
When the economy crashed, only a few companies were able to keep investors onside.
The verb "get/keep" must be conjugated according to its tense.
The origin of this phrase is not clear.
hurt someone or yourself
If you try to carry that suitcase, you’ll do yourself a mischief.