It's the simplest thing I've ever seen but it works wonders!

It's this silicone circle with a little boy at the top that acts as a suction cup for just about any standard cup size. Once you plop the cup cover over the opening, the suction is so strong that you can actually lift the cup up by the little boy at the top.

There's no effort at all in putting the cup cover on. You just literally place it at the opening of the cup and then you're set. No extra pushing or squashing needed. It just automatically creates suction. AWESOME PRESENT