I was observing a sparring session between two of our blue belts the other day. They rolled nicely, but as I watched them I noticed a recurring pattern. The other always ended up being mounted and the guy doing the mounting went for an americana lock. This happened several times. It also happened with him going for the armbar.
The thing is; the other guy has really flexible arms.
So the guy trying to submit was spending his strength on trying to get the same submission.
Turns out that it might be better to try and get a choke submission if the guys arms rotate fully around and he’s not tapping. If it happens several times you might consider moving on to another type of submission.