Working on the sippy cup

For a while now, Gracie and Luke have been trying to hold onto their bottles. They've had various amounts of success with getting their hands around the bottles. Mostly, they like to play with the plastic drop-in and make crinkly noises with it. I read somewhere that babies at this age might be able to handle a sippy cup. So, I bought one version, but they did not know what to do with it. The mouth/sippy part was too hard. Daddy took us to the store and I found the Gerber sippy cup with a slightly softer sippy part. The results have been mixed. Despite the protection of the "leak-proof" sippy seal, most of their drink ends up on their shirts.
Who knows. Some day they may actually have it mastered.