After you’ve washed your hands, use your thumb and pointer finger to reach up and grab the base of the cup. Do NOT yank by the stem. You need to release the suction before removal. Pinch the cup to release the suction, and then slowly remove the cup.
Usually you'll be sitting over a toilet or in a shower, you can remove the cup and dump the contents in one swift motion.
After you've removed the cup, rinse clean, mild soap optional, and you're ready to reinsert! If you're in public, feel free to wipe with toilet paper before reinserting. While you wouldn't want to do this every time. It's perfectly acceptable in a pinch.
One (of the many) pros of our two-pack is that if your sink is far away from your toilet, you can bring your clean one in with you, empty your cup, insert the clean one, and wash the other on your way out, leaving it ready for the next switcheroo.