Is it plastic or silicone? Sometimes they start to smell and make the water taste bad.
We have the dr Brown cups. He was obsessed with it, I’ll try a different one see what happens
Throwing is very developmentally normal at this age 😅 so it could just be that
Could def be that. He’s definitely trying to see what he can get away with these days
maybe try a different type of straw cup? or a sippy. my youngest will only drink from certain straw cups and he likes the dr brown sippy cups too