Yep you can have an upper or lower......with the upper you drink the barium, with the lower it is inserted in your tushy.
If you are having the upper, as k for a roll of paper towels when they have you start drinking the barium. I used the towels to wipe my tongue after every swig and it made it easier to get all of it down. Also be prepared as it may take a while for this test. If things move slowly, they will keep taking xrays until the barium gets to where it needs to go. However, if you are low on inflammation or strictures or have fast motility, it could go quickly.
If you are having the lower, you will really feel a sense of urgency as they insert the barium, but they prevent any from coming back out.
As with most tests, I think the prep is worse than the actual test.