Find yourself mounted. Don’t make it obvious that you want to work from the mount. Just let your guard down a little. Then explore that position without any great need to get out. But don’t lay there and be passive either. Feel your way around and try to move in many different ways and analyze the problems that stop you. Be curious and scientific, try lots of stuff, don’t use strength or speed, stay relaxed. Do this with someone who isn’t a meathead at first. But ultimately do it on the meathead too. When the time comes that you need more challenge.