You'll need to first practise jumping into close guard position while standing up. This way the other person also works on his base. After your both confident in jumping into each other's guard, you'll want to practise jumping into arm bar position without locking in the armbar yet. So grab each others arm while the other arm hugs the neck for support, this way you'll have something to hold onto so you wont fall. Keep practicing these movements until your confident and make sure you take care of each other. And always ask your instructor for advice!

That is some crazy thing man you got to find a wrestling ju jitsu teacher.

You have to learn how to fly first.

DONT do it..... When you are good enough and fluent enough in techniques then it will eventually help. Then you can ask your instructor to help you through it.

So I practice Brazilian jiu-jitsu and I'm wondering how to practice a flying armbar safely. With most other submissions you can do the step by step, but with a flying armbar there's not really a way to do it slowly, and it seems like if you do it wrong you could get really injured. I'm wondering if there's a way to practice each of the steps without injuring yourself or the other person, when neither of us has done it before