Breastfed 10 month old transitioning to sippy cups

Any tips on how to transition properly?

Does water only go into sippy cups at first?

Or do I try cold turkey all breast milk and water into sippy cups?

I'm currently using playtex 6oz bottles with my breastmilk. He'd rather have my nipple even though we've been doing bottles, pacifiers and breast since birth.

I have nuk brand, and a few random brands from walmart yet after a few attempts he flings the sippy cups with water across the room. (Side note He will drink water from a bottle)