I love this topic. Not for the fact that the thread starter has an awful open guard, but because the guard is my preferred mode of playing the whole BJJ game.
I'm 5'7", 150lbs. In our academy, the only people who are remotely close to my weight are some of the women, one of the instructors, and the big 14-15 year old kids. Most everybody's in the 180-225 range. In this scenario, I prefer not matching strength from the start of rolling, so I end up in my guard. I'm relatively strong so I probably could if push comes to shove, but I've noticed I last longer and get more rounds if I just... CHILL....
So I end up in the guard a lot. Open guard, most often, because most everyone in our academy is pretty good at avoiding being locked up in someone's closed guard. What I find really useful is just being comfortable twisting yourself in weird positions as if you were doing yoga. Learn to be comfortable doing lots of rolling over the shoulder, getting in inverted guard position, and just playing around on the mat by yourself as if you were a little kid (my nephews and nieces, when they were young would always crack us up by rolling around on the floor for fun).
I find that while these positions may not necessarily be used in the roll, the mechanics and feeling of it all help to make you comfortable thinking, "Some way, somehow, I'm going to get my legs between you and me again." When they have both your legs to one side, rolling onto your far shoulder to windmill your legs back into place isn't an uncomfortable prospect anymore. If they've begun to pass such that they've scissored your legs (your bottom shin is across their belly, top calf is somewhere across their throat) and you don't seem to have space to get open guard back the normal way, roll inverted through to get guard that way.
One of the assistant instructors told me, "Open up. Have fun with it. Too many people get concerned with being safe all the time. Take risks, make your mistakes here to learn what can work for you."
I've since taken the point of "playing around" and ran with it, and it's worked wonders for my guard. I guess this ties in excellently with another thread on this forum about overthinking BJJ. Many times I get into positions that were never taught, and don't even have names, or some weird guard variation that has yet to be formalized. But I clearly see in my partner's face that he/she finds it strange/confusing, and it makes me happy.
One drill that I love doing is on those padded posts that are usually found in the center of the mats at most BJJ academies. I lie on my back and post my feet on it, like it were someone's hips. I crisscross my legs then roll into inverted guard position, keep rolling, and come up the other side. Then back. Lather, rinse, repeat. Very fun exercise, and for me has a lot of "wheeee!" factor. LOL.