I've just done this with DS2 (did the same with DS1 at 16 months).
I tried night weaning DS2 at 12 and 15 months but he wasn't having any of it - would wail for hours
Right, the 1st night is awful, absolutely awful. You have to want to do this more than anything else in the world.
make sure your DS has had an active day and well-fed. Bath at normal time, then off to your bed for a couple of books. Keep it all calm - no leaping up and down the bed. Lamp for reading then lights off. He'll get tired...........and kick off big-style when you refuse the milk bar. Have water handy as his throat may get sore from screaming. If he's dog-tired, he shouldn't scream for much more than an hour. You're there, cuddling him, soothing him. There's an alternative to boob, he'll adjust! He'll thrash around a lot, cos he'll be as mad as hell.
During the night, he'll wake and you just cuddle him, offering water.
Next day, offer a feed when he wakes. Make sure he gets a mid-morning snack, offering boob if he asks - but DO NOT let him fall asleep. Take him up to your room and repeat the whole wailing business.
You should see a huge difference in his night-wakings by night 3. You may find that he still wakes as often, but settles v quickly with a cuddle from you.
If things have definitely settled down, get your DH to put him down at night and also for his daytime naps at the weekend. Your DH will have to go through the whole wailing business again, but it shouldn't be nearly as bad as it was with you.
After 2 weeks, or whenever you feel he adjusts to his new routine, transfer the whole routine to his own bed. If he wakes in the night, welcome him to your bed.
The final step is returning him to his bed if he wakes in the night.
The whole timescale is clearly flexible - you have to judge when your DS is settled and ready to move on.
It is tough listening to your child cry, but remember you're there for them. You're offering comfort, just not in the form they're used to !