This guard is the only guard where I get swept at will.
It seems that the person is always able to pull my weight forward and on top of them and then roll me over.
What is proper posture when inside a butterfly guard?
thanks!
This is some of the little I know about this subject, i.e. one decent (and common) posture against the butterfly guard (I'm probably missing a detail or two that Michael Jen would be able to add):
Put your face in his chest and drive him flat on his back. He wants to be sitting up with his head below yours, you want him flat with your head in his chest. When he's flat on his back, he's got a lot less sweeping options. Also, with your head in his chest your weight is more back so he'll have a hard time pulling you forwards to sweep you (you'll feel heavy). Finally, he can't sit up to sweep you backwards.
Now pin his hips (or should I say, severly restrict his hip movements) by letting your elbows touch your knees. You kind look like you are "turtling" in the back mount. Your elbows should be at the side of his hips. His feet should be jammed up against his butt and his knees should be close to your rib cage (he wants space between his hips and yours - let him have next to no space). In addition to the benefit of flattening him out, now he can't pull his legs out to take your back and he can't move his hips.
Here's one guard pass from there. With your (say) right hand, reach behind his butt and grab his left ankle. Push it to the inside and feed it to your other hand - your left hand. Now, grab his ankle with your left hand. Next, pass his guard by walking around his trapped left leg. You will probably have to raise your hips a bit when you go past his left knee. Once you grab the ankle, you can pass the guard very slowly and hum your favorite tune while doing it, just to annoy him.
Hope this helps,
jonpall.
Personally, I'm not a believer in any sort of static "posture" when it comes to open guard. Posture is fine for closed guard, but not as good for open guard. In the closed guard, good posture forces your opponent to move if he wants to accomplish anything, thus forcing him to uncross his ankles which gives you the opportunity to pass. When it comes to open guard, I want to limit my opponent's movement, so static posture is not as beneficial.
For any sort of open guard, don't think about posture. Think about attacking with your pass. Make him defend your pass before he can start his offense. Do you know any butterfly guard passes?