C.S.
I have a 10 month old daughter and I gave her a sippy cup at around 6 1/2 months. She struggled with it, but it gave me an idea of when she was thirsty for water and not for breast milk. I would suggest putting it on the table/high chair for him for now and, even if he only plays with it, he will soon get the idea and the exposure is great for his hand to mouth skills. As a side note, I haven't given my daughter juice at all.... After struggling with my older daughter now to drink water, I use juice as almost a treat, but water with meals and in-between.... (but definitely dilute it 50/50 with water if you choose to!). Congrats on your first born!