Oh really, was the batter quite firm then? I have to admit, I felt so stupid handling that piping bag, you should have seen me haha. Would have been a funny home video :)
Practice practice practice I guess...

I also used the rubbery one but without screw, it did move once though, that I had to pull it back down to the hole, but for the rest it was quite nice. I just shouldn't fill it up so much to avoid the mess on the top of the bag.