The Cocoon Armbar from the Butterfly Guard starts from the Modified Cocoon position. I started doing the Cocoon with this wrestling collar tie because it gives a lot of control over my opponents upper body.
Instead of an overhook and an underhook I control my opponents neck and tricep with his arm trapped to my body.
From this Modified Cocoon you can still hit the sweeps that are in MTRG. You can also land this armbar, a triangle etc ...
If your opponent tries to stand up you can also transition to the X-Guard with all of it's options to sweep them.
Here I start from Butterfly Guard with my opponent in the Modified Cocoon. My right hand is controlling my opponent's neck while my left hand is gripping his tricep tight. I am also pinching my left elbow tight to my body in order to trap his forearm.
Also, my head is against his head & collar bone and my Butterfly hooks are giving pressure up and outward so that they are active.
Next I release the B-fly hooks and bring my feet onto my opponent's hips. I maintain a nice tight collar tie as I pull his upper body towards me and push his hips away with my feet.
Now I pull my opponent's upper body and push his hip away with my left foot as I bring my back to the mat. As I am doing this I bring my right leg high up into his armpit with downward leg curl pressure.
With the right hand that was at his neck I push his head away, bring the left foot off of his hip, up and over neck with a leg curl to setup the Armbar. Then ...
Lift my hips to get the tap.
From this angle you can see the tight collar tie with my feet already on my opponent's hips ...
Here you can see I have put my back to the mat and pulled my opponent's upper body forward by pushing his hip away with my left foot and bringing my right leg high up into his left armpit with downward leg curl pressure.
Then the hand that was controlling my opponent's neck pushes his face away as I bring my left foot from his hip over his head. I am still gripping his tricep with my left arm and doing a leg curl with my right leg to control his posture.
Once my left leg is doing a leg curl over his neck I raise my hips while keeping his right thumb pointed up towards the sealing to get the tap.