Sippy cup for use with child with CP

Can anyone give me advice on which sippy cup to use for a child who gets the majority of his nutrition from Pediasure, both orally and through a G-tube. He was using a bottle but is starting to reject it (before we have had success in replacing it with a nosey or other cup) We need something he will accept and be able to use successfully to obtain a good quantity of nutrition, so that we do not need to increase his G-tube feeds. He needs something which will control the flow as he has C.P and some problems with oral skills.

Thanks for any ideas you may have,

Heather McKenzie