Hey I don't have an answer when playing the sit up guard besides wrestle up. Is there any attacks that I can do sitting?
Besides wrestling up you can attack dummy sweeps. Armdrags and 2-on-1 drags are possible if they reach with their hands and finally you can snap them down if their head is in range. The other thing you can do is try to transition to another guard such as shin to shin, SLX or leg entanglements.
IMO the main idea behind sitting guard is to get the other person to fall into your tempo as opposed to stalling you out. If you chase after someone with wrestle ups and dummy sweeps they will sit down and from there you can play whatever guard you want. Sitting guard is great for keeping people honest, especially is you have better standing grappling than they do. It makes your opponent get down and engage your guard.