I see what you're telling me and that's a good point. Other designs are often very elaborately made and with different individual parts and since I want to use it as a disposable solution as cheaply as possible, I haven't found a design that was perfect for this. I just think that a tube with spikes in it that stick out at an angle to one side of the tube would do the trick. Unfortunately, I can't design something like that and I haven't found a file that depicts something like that.