Whats up guys. I try to work my half and open/butterfly guards a lot because I am a guy with short legs. In tonights class we started from half guard to do a little light rolling and I was paired up with someone pretty much my same height and weight and a little more experience. The problem was every time I was working my under hook from the bottom of the half guard he was very aggressive in reaching for that arm while I was trying to work my sweeps. I think a lot of my problem was that I was rolling lightly and he was going near 100% but I have also encountered this problem with a lot of big guys. I get stuck under them while going for a sweep and while I am trapped they just reach for my under hook and Kimura. Anyone have any advice for preventing them from doing so? Should I focus more on keeping my under hook really high and tight to their backs. Should I try and time my sweeps better so that I do not simply phail the sweep attempt, thus leaving my under hooking arm vulnerable?