Out on a Limb
Definition: To put oneself in a risky situation, usually for someone else's benefit.

Example: "What do you mean you won't be my business partner?!" John asked. "Especially when I went out on a limb and violated company policy to get you those clients!"
"I just dropped off my thesis. You were so incredibly helpful in this process. I work full time and knew that I would not have time to go over 80 pages with a fine-toothed comb the way that you did. "
Name Intentionally Withheld
Graduate Student
Case Western Reserve University