put (one's) ass on the line

rude slang To personally assume or expose oneself to some risk, danger, or responsibility; to imperil oneself or put oneself in harm's way. Look, I'm putting my ass on the line for you here. I could get fired if they find out what we're up to! You have to take some risks to be successful in business and in life, but don't put your ass on the line for no good reason.