Kesa gatame -> armbar

I have kesa-gatame on B's right side. I have B's right arm tucked into my left armpit and my right arm underhooks B's other arm, securing it by gripping my own collar.

Step 1: I bring my left leg over B's head and bring their right arm diagonally across the body.

Step 2: I sink down and use my armpit + hips to initiate the armlock

Step 3: If B escapes their arm, I spin and armbar the arm I have trapped with my own collar

Armbar from kesa.
-From the same position above I make sure that B's underhooked arm is trapped on top of my shoulder and secured by the collar grip and my head. If B tries to bring the arm across my face to push me away, I catch it with my left hand and lock up an americana. Otherwise..
Step 1: I bring the underhooked arm down towards B's waist.

Step 2: My forearm/elbow comes across B's stomach and I put all my pressure through my forearm.

Step 3: I release my collar grip and my hand slides to behind B's elbow

Step 4: While mainting the pressure with my head and forearm, my left hand comes up behind the elbow on top of my right hand

Step 5: I can go knee on belly and then post out my left leg to finish the armlock