He actually won't take a bottle at all; I've tried at least 4 kinds, with all different nipples... I've tried 3-4 different sippy cups, even with valves removed... nothing works. He refuses to be supplemented, wants it straight from the source!
Which I have no problem with, except that he's not gaining weight (actually lost 9 oz from one checkup to the next, and when he only weighs 15 lb 13 oz, 9 oz is pretty big).
We've never had any nursing problems, he's been a pro since an hour after he was born; but about a month ago I guess I had a drop in my supply, which I didn't notice until he had failed to gain weight between 4 and 6 months... I managed to build my supply back up by nursing almost constantly (it seriously felt like I nursed him every time he opened his mouth), and now we're going strong again, other than the weight thing.
I hope to supplement him with my own milk through the SNS/Lact-Aid, which I am hoping will help to keep him from noticing it so much. My worry though is that he'll notice the tube and want to play or bite it (and me), as that's all he will do with a bottle/cup lately.
Also, I tried a makeshift SNS system the other night, using a tube from a breastpump (obviously too big, but I was desparate!), and it almost worked, except that he kept getting distracted by the tube and biting me

I guess the SNS/Lact-Aid's aren't usually used by moms/babies who have breastfed well since birth, but I don't know how else to supplement him...