For subcutaneous (subQ) injections, insert the needle at a 45- to 90-degree angle depending on how much tissue you can pinch. If you can pinch at least an inch of skin, 90 degrees (straight in) is fine. If you're lean with less tissue, use 45 degrees to avoid hitting muscle. Pinch the skin, insert the needle smoothly, inject slowly, wait a few seconds, then withdraw. Don't aspirate (pull back the plunger)—that's an outdated practice for subQ injections.