I did the same as Mummyof 2 - went straight to a regular cup and it worked well with my first. Doing the same with my second (9 months) now. He too is totally bf. I started giving him the cup a few weeks ago. At first he did nothing but play with it and get water everywhere. Now he's getting the hang of it and will drink a bit before I offer him his after meal bf.
Good luck!
Good luck!