1)Steal your thunder:
Brad stole his older brother's thunder by copying his brilliant art homework for school, and claiming it was his.
Brian stole Erics's thunder in the 100m race even though Eric had prepared for much longer.
Alex stole his brother's thunder by bringing home a more beautiful girlfriend to meet their parents.
Definition: to take credit for something someone else has done. Or to take attention away from something someone else has done.
Etymology: in the 1700's, a bad American playwright called John Dennis produced a play that used his new thunder machine. But his play was so bad no one paid attention to his new invention. A few days later another playwright used Dennis' machine to great reviews. The term "Stealing someone's thunder" was a news caption
2)Devil's advocate:
Roy played Devil's advocate on the murder trial jury. He forced the other jury members to spend two days away from home.
Eric played Devil's advocate and prevented a new bill from being passed.
Annie played Devil's advocate when she rightfully disagreed with the decision to ban candy from the town.
Definition: someone who takes the opposite side for the sake of it, even if they don't necessarily agree with it
Etymology: The background of this word comes from an official position within the Roman Church, in which a canon lawyer called the Devil's Advocate, argued against the sainthood of a candidate in order to uncover any character flaws or misrepresentation evidence favoring canonization. It is now in common usage outside religion
3)In my corner:
After Tony stood up to his bully, all his classmates got into his corner
Ronald got into his brother's corner by confirming he was not at a crime scene
Andrew had no one left in his corner after it was discovered he beat his wife.
Definition: support
Etymology: Derived from boxing, where each boxer has his own corner, where his coach and others give him water and other refreshments to support him