If you have the flexibility to double bag that will help with people standing up to escape your rubber guard. As others have said the "Drop Kick" sweep from a stacked rubber guard is a great move in that situation too. Keeping things as tight as possible helps too and pay attention to what you are doing with your weak leg (leg not being used to establish the rubber guard.) What I like to do against guys I know that will try to stack me and stand up is get to invisible collar as quickly as I can for me that usually takes the path of new york (free or step by step whatever ends up happening) to crackhead control (keeps a lot of pressure and weight forward of there center of gravity making it tougher though not impossible to posture out/stand up, at least that's what I think is going on haha) to invisible collar (sometimes when I clear the neck to go for chill dog my "weak" leg losses it's position in crack head control and I have to quickly adjust to fix up my invisible collar but it isn't too big or difficult of an adjustment.) Once someone is put into invisible collar, if you are doing every thing correctly of course, there is so much pressure on their neck that they won't really be able to stand up and even if they could their mind isn't thinking about that, they are thinking about defending the submission at that point whether it comes from invisible collar itself (some guys tap to it occasionally) or from wherever you decide to go thereafter. Good luck hope this helps.