If you used the method my young lady friend used then all you have to do is keep the tube inside you when you go to test. While sitting on toilet and holding cup take a finger and push a hole into the foil and let sample flow into their test cup. Good Luck........

EDIT....I think the gray tape might do better then rubber bands. Fluids can still leak through something rubberbanded......but not through the old fashion gray tape that waterproof.