I don’t know what the policy is at your church nursery, mother’s morning out, or daycare, but where we live one has to have their child’s name on their sippy cup or else. I have tried using my labeler – – it comes off in the wash. I have used permanent marker – – it comes off in the wash. What’s a mom to do???
A company called InchBug has come to the rescue with an item called the BumpyName Orbit Labels. You have got to check this out. KB has her set arriving in the mail and I believe it will be worth every penny to not have any discussion with nursery workers, teachers, and her older siblings!
thebluehutch.com 
here’s another idea…i stole it from someone else. get a wide piece of elastic and sew it so that it makes a circle that will fit snugly on your cups. write their name on it with permanent marker. works like a charm!
That is what I give as my baby shower gift to all the new moms in our church. It is so fun to have something with your child’s name on it and it is useful!