Vise grips! Wow, that is inventive! I know there are some quilt contraptions out there, if you are trying to tame to large roll to your left side, but also can be used to keep the roll on the right side under control (so it will fit through the harp).
I tried a friends' red sort of hard plastic "C" that fit over the roll, not a fan. I just puddle and flop like the others here. I think it takes a little creative manipulation: I start in the center, work outwards on 1/4 of the quilt and stop and start all over for another 1/4. Not the way our heads tell us to do it...but it works for me.