God I hate yoga. Let's just start with that. But just because I hate it, doesn't mean that I don't think it is amazingly beneficial - especially for guys. There are a lot of people who love yoga and a lot of people who hate it. Its extreme polarization is exactly the problem with yoga. Lots of people (mainly girls) have become so obsessed with yoga that they don't do anything else. And there is a whole other crowd of people who think that yoga is so incredibly lame that they refuse to do it. Unfortunately, these are usually the people who could benefit the most from yoga.
Men, boys, guys, dudes, bros - you need yoga more than the ladies do. I look at my dad now at age 65 and see a cross between a robot and Frankenstein. He has worked out literally every day for at least the last 40 years. He skis, plays tennis, plays golf, bikes, runs, works in the yard, lifts weights, windsurfs, and plays soccer. Well, he used to do all of that. He still looks like he is in incredible shape. He is tall, strong, and cut. But then you see him walk. He has bad knees, a bad back, bad wrists, hurt shoulders, destroyed feet, etc. My dad can't bend in any direction.
Guys are hard on their bodies. Some more than others. Those who are hardest on their bodies are those that need yoga the most. We need the flexibility and strength that it builds unlike any other exercise. It will help you avoid injury and allow you to play sports well into the future. My girlfriend forced me to first go to yoga the first few times. Then my dad woke me up to its absolute necessity.
Unfortunately, I can't sit here and explain how to do yoga exercises. I am no expert - I just pay $5 to go to class and have someone tell me what to do. It's really the only time I ever pay for group fitness. There are also plenty of youtube videos.
Go do yoga once per week. You are going to be terrible at it. I am terrible at it. You'll get over that though and you'll be better off for it in the long-term. Check out Adam Levine doing some yoga for Men's Health - http://www.menshealth.com/celebrity-fitness/adam-levine