Adding Lactose Milk Sugar

I'm brewing a chocolate porter and am planning on adding milk sugar to sweeten it up a little. I've read 4 oz. is a good start for 5 gallons. Do i need to do anything? Bring water to a boil, add the lactose to the water and add it? Or do you just add the sugar directly to the bottling bucket...

Goes into the boil. I think a late addition will work fine. I actually have NB's milk chocolate stout in secondary right now and that has a lb of lactose in it for 5 gallons. Tasting the wort before fermentation and it want crazy sweet. Really depends on why kind of roasted malts you put it up against.

For a cream/sweet stout, I also use about 1 lb of lactose per five gallons. I don't think its really sweet, though, not in the way that you think sugar is sweet. Its more about mouthfeel and fullness than the flavor of sweet. I also add it at the end of the boil.

I added lactose on my last sweet stout- 1 lb for 10 gal batch and it didn't get significant fullness to beer. I think I'll go with 1.5-2 lbs next time.
As said, add it at the end of boil, just to sanitize and dissolve it.

Lactose is not very sweet- try some when you put it in your beer. I would call 8oz the bare minimum for a 5 gallon batch, but I think a pound is more standard for 5 gallons. I would actually start with a pound and adjust down if you think it's too sweet next time. My chocolate stout, which would be sweet without it, uses 12oz.

i just made a chocolate milk stout (eviljays) and used 1lb of lactose in 5ish gallons (i ended on the higher volume, lower gravity side) i think i added it with 10 minutes to go left in the boil. when i drank the sample i used for OG it was sweet and dry and the back end was full and a little dry, just what you would want from a milk stout, 2 weeks later and i can barely taste anything but a dry lactose twinge on the back end of my stout sample, needless to say it was an awesome addition for the first time ive brewed with it

2 lbs in 12 gallon batch, not super sweet but has a very nice mouth feel and creamy head.