I have introduced Allister to his first sippy cup. Yes it's super early. But we have our reasons.
Firstly, I think its probably nice to have a sip of water when you eat, not have to wait until your next feed. Also, Allister, like Harrison, doesn't really like a bottle. With Harrison he was drinking well from a cup at 6 months, so I could just skip bottles and put my milk in a sippy if I was not around to nurse.
Don't worry, we are not giving Allister a ton of water! its literally just a dribble, not even 1/2 oz! Its just practice for now.