Guard Pass Counter: Yay or nay?

[Ungjaevel]

Tonight at practice, I was rolling with another blue when I hit a sweep/guardpass counter. I've never seen it before and I'm not sure whether what I did is nonsense that will never work again or if this is something legit.

What happened was this: he was passing butterfly by squashing my hooks, trapping them on the same side of his right (my left) leg, snagging my foot with his hand, pushing my knee with the other, and hip switching to side (towards my left).

I noticed that the arm he was trapping my foot with was flared and he hadn't flattened me out yet so I was still able to sit up. I reached across his body with my left arm and got an underhook; I met this arm with my right and gabled such that my forearm was across his neck. As he hip switched, I was able to torque this grip and sweep for mount. The whole thing seems similar to this move:

I realize that this happened because I had let him get too far in his pass (I fucked up a long time ago, thanks Kurt O.) but is this worth keeping around as a last resort? Is there some way I'm going to get boned that I'm not seeing?

[GoldenJonas]

It is a legitimate counter...where your opponent REALLY REALLY screws up on the "Butterfly Guard, 2/1 Hip Switch Pass".

What is good, is that you recognized the mistake and took advantage of it. Whereas, your opponent should have bailed on the pass attempt as soon as you started to come across his back.

Good recognition of the mistake and good set-up and use of a valid option under the circumstances presented to you.