Summarize this article in one sentence.
To bump, you'll need to squat until it looks like you're sitting on a chair. Stick your butt out so it goes past your heels, and straighten your back. Your posture is correct! Make a fist with your dominant hand. Cup your opposite hand around that one. Don't cross your thumbs, but keep them parallel to one another. Straighten your arms out. Feel the flat part of your forearms (smooth inside part). This is where the ball will make contact. This is one of the most crucial and most used moves in volleyball. Move your feet to square up with the ball. When it is almost touching your arms, take a step forward, hitting the ball with your arms, or platform (flat part of arms). DO NOT SWING. Use your legs to push up and out to target, and your arms should just move with them. Don't swing your arms more than 2 inches (5.1 cm). Passing may sting. An easy way to keep from stinging is to simply shrug your shoulders when you hit the ball.

Summary:
Position. Hands and arms. How to do this move.