Sometimes a picture is worth a thousand words.
If I was training my daughter in the etiquette of sharing water from the same bottle, I'd probably say something along the lines of:
Pour the water into your mouth, like this –
and at this point, I would demonstrate, and then I would elaborate with a clarifying remark, such as:
– and don't let the bottle touch your lips
or:
– and don't put your mouth on the bottle
This method has two advantages:
- first, it shows her visually what you are trying to do,
- second, if she messes up and spills the water, or puts her mouth on the bottle, you've already had your sip :^)
Incidentally, this takes some skill. It might be best to exercise some foresight and have the child practice the technique at home. Until the skill is mastered, you can simply give the bottle to your child last and let her drink the remainder in the normal way. (But this is not parenting.SE; I'm digressing now.)