From Jeremy Arel: In this video I show the Guillotine Choke from Half Guard Reverse Sit. Typically it’s easy to scoop the head when your opponent is on his/her side and it can be a real surprise.
Initially when I started doing this I would just threaten the submission to get the pass but in the last couple of months it’s really gone the other way. Now I often go for the submission and I’ll take the pass as a consolation if the submission does not work.
Once you have lassoed the head you’ll want to turn back towards your opponent, place your head on the floor and base up on your toes. There is a little spatial control in this position where you need to stay tight with your hips and knee so that your opponent doesn’t try to slip back to closed guard, but in all honesty once you get your hands connected and you’ve “rocked the baby” your opponent will not want to go back to Closed Guard.
Make sure to reference the video to see how I manage the space between our bodies. This can be a real problem and is usually the deciding factor in whether or not I finish this move (in no gi it’s so easy it’s almost comical).
After you learn to manage the space and “rocked the baby” it’ time to turn your core. You’re going to find that as you turn your core (both by pushing down with your pelvis and by crunching your ribs) your knee will often pop out. If I can my knee free and placed on the floor then I will reassess the situation.
If I think I can finish the choke I keep going, if I feel like I’m just tugging on his/her head then I’ll let go of the head, lift my head and transition into a 3/4 mount position. My first order of business is to cross-face them with my outside arm and flatten them out. How you transition and where you go from here is up to you !