A unison bend is a very cool trick that makes your playing sound super rich. Here's the lowdown: Basically, you're going to play two strings at the same time but bend one of them to match the other's pitch. Normally, you'd bend the lower pitch string.
Let's say you're working with the G string. Put your ring finger on it at the 7th fret. Then, your index finger goes on the B string on the 5th fret. Hit both strings together. Now, keep your index finger steady and push the G string up with your ring finger. You're aiming to make the G string sound just like the B string.
When you're starting out with this technique, one thing to really focus on is your finger strength and control. Bending a string to the exact pitch can be a bit of a workout for your fingers, especially if you're not used to it. It's not just about pushing the string; it's about controlling how much you bend. You want the two notes to sing together in harmony, not sound like they're in a bit of a tussle. A good way to practice is to play the note you're trying to bend to first (that's the note on the B string in our example), so you have that pitch in your ear. Then when you bend the other string (the G string), you can try to match it to that sound. It's like playing a little game of 'match the pitch'.
You might find your fingers getting a bit sore or tired, and that's totally normal. To make it easier, use your other fingers to support the one doing the bending. If your ring finger is doing the bend, your middle finger can help push, and your index finger stays put on the other string. Also, don't be shy about using a bit of your wrist and forearm to get that bend. It's not just a finger move; your whole hand gets in on the action. And remember, the more you practice, the stronger your fingers will get, and the easier these bends will feel.
It might feel a bit tricky at first, and it's all about listening to get those pitches matching. Don't worry if you don't nail it immediately; it's something that gets better with practice. A few quick tips: make sure your guitar is tuned up before you start, use your other fingers to help push the string for the bend, and just keep at it. The more you practice, the easier it'll get. And that's pretty much it. Give it a shot and have fun with it!