Is it normal to drink water from sister's water cup?

its fine but i wouldnt do it personally

Do you really have to ask if that is normal? It's your sister, that's totally fine!

Probably won't hurt you any. When I was a kid we had a bucket that we carried in from the well outside. The bucket had a long handled dipper like you see on cowboy shows. We would dip some water, drink it out of the dipper and drop the dipper back into the water. The end of the handle hooked over the edge of the bucket. Everybody drank the same water from the same dipper, and it often sat over nite or all day, uncovered. None of us knew anything about germs and nobody got sick. If somebody was over, guests, workers, or whoever, they used the same dipper, if they wanted a drink.

Sure. I dont understand why it wouldn't be. Unless it has been sitting over night. Then i find it kind of disgusting.

It's fine, just make sure she's okay with it and she's is not sick!

Uhhh ok

what is a water cup?

I used to do that too, but my sister has her own house now :(

I am awesome