Knowingly and willfully pursuing a high-risk course of action with reckless disregard for potential consequences.

A phrase drunk mountain bikers use to tell each other to hit massive jumps or do something stupid.

Rock climbing: Used to encourage a fellow climber to finish a route or problem. Similar to and interchangeable with "allez!" (French), or "dale" (Spanish)

Whole heartily throwing caution to the wind.

1. A response to "Can I ask you a question", or when someone says "Let me tell you...", Listen up!", etc.
2. Response to "Round(s) on the way". A military term used on a firing range, usually at the screen line, usually involving large bore weapons.

Do something that scares you.

Elton Castee from TFIL
Youtube

Texas Hold 'Em Slang phrase: when you are confident about your hand