I read in an aba mag about a woman with a similar problem, and she started getting the bub to suck a washer in the bath and then started putting the washer over the bottle teat and then from there bub associated sucking with the bottle. Not sure how old her bub was though.

You can break the no spill valve of zippy cups...dd used to chew through hers.

If you go for a straw cup, make sure it's one without the valve (ie the cheaper the better).

Otherwise I would be cup feeding.

Good luck!