It took my daughter a few days to even wanna try out a cup and she was super mad but she did fine and she didn't make a mess or drop it to often, but her brother would make her drop it, or get her in a hurry. Always a mess to clean up when your a mommy
Why don't you just get rid of it? That's what I did with my daughter, she could never keep up with it, I would spend more time looking for it then she would use it, so why not just toss them all and start on a real cup, I used a cup when I could stay close and I also used a cup with a lid and straw. Just an idea