My dh starts taking over at night when we reach that point. When they get really upset, he will bring them to me, but mostly he just keeps them from seeing me, gets them a drink and a snack, and puts them back to bed. And, for some strange reason, they go to sleep. If I tried that...whew...
But, while that has worked for our last 3, he was deployed during our second pregnancy, and I was on my own with my first child...and addicted nurser. Here's what I did on the very slow and long process...
1.) Took a sippee cup with water to bed with us, and tucked in it where she could easily find it. (She was still co-sleeping at this time). When she woke up, I played dead. (By the way...the first time I did this was a night where she had been nursing for HOURS, and just wouldn't give up). I just layed there "sound asleep" while she fussed and wallered all over me. It actually took a lot less time than I thought. And, actually, I took the cup to bed the second night. In the morning after the first time I did it, she really gave it to me in the morning, "Mama, at night I firsty! I firsty, Mama!"
2.) Thought really hard about the reasons she might be waking up, and tried to address those:
a.) too hot or cold? change in thermostat or pajamas
b.) thirsty? dry mouth? add a humidifier
c.) hungry? big bowl of oatmeal before bed
d.) bumping into me? pulled in part of our sectional and made our bed "bigger", so she had plenty of room to flop around in her sleep
e.) teething? those two year old molars can be a doozy.
f.) pregnancy? did you know that as your pg progresses, your milk changes and starts to taste salty? That just makes the nursing babe more thirsty, and in their sleepy state, they seek to nurse more. Sometimes, with various ones of ours, I would preempt the nursing by giving them a drink when I first saw them rousing. OR, I would just get up and go in the kitchen, wake them ALL the way up, and give them a real snack and drink. It might take a while to get them awake enough, but it's worth it.
3.) After she got used to not waking up at night, I eased her into her own bed. I would read story, after story, after story, after story to her in a very soothing and calm voice, slowing rocking in our rocking chair. When I could tell she was really, really sleepy, I would suggest nursing to her, but she could only nurse for one song. In the beginning, I would sing tons of verses of the same song (so she would get the idea), until she was asleep and I could lay her down. Gradually, over the course of 4 months, between big drinks, big bedtime snacks, and long bedtime routines, she started falling asleep quicker, and easier...and then, right before ds was born, she started just getting in bed and going to sleep.
It was so gentle and slow. It was perfect.