Before we went we had a wonderful drinking cup with a silicone straw that didn't leak at all. Thanks to the ridiculously long journey here we decided to leave it at the airport in Sao Paolo on the way here. It was so useful that we made it our first priority to get another one in Santiago.
We have now bought 3 replacement ones and finally found one like it (far left)
Leo has it next to him in the trailer and every night we also put it in his bed so that he can have a drink if he wakes up. He now does this regularly and goes straight back to sleep. Leo's favourite one is the middle one but it leaks a bit despite the promises on the packaging.