"Bebe más agua por favor."

I know. This app is great for how words are used but it doesn't explain why.

Imperative tense: Tu bebe, tu no bebas, usted beba.

I think it because 'usted' is formal for 'you'. Therefore it's 'usted bebe'.

I believe I remember that "bebe" is used instead of "bebes" whenever it is spoken as a 'command'.

it is supost to be: Drink more water, please

IT sounds much better if you say, "Please, drink more water." but, "Drink more water,please." is fine to I think.

Thats what I thought as well

"Bebe" is the second person imperative, informal, of "beber." You are asking your friend "Drink more water, please." There are other imperative forms for Usted, ustedes, don't drink, and so on. "Bebe" is the same as "he/she/it drinks," so you need to take the cue of "por favor" to see it is an imperative. Not easy to understand the first time ... or the next ...

Imperative, 2nd person of "beber":

SINGULAR

bebe (tú)

bebé (vos)

beba (ud.)

PLURAL

bebed (vosotros or vosotras)

beban (uds.)

Yeah "drink water it will get rid of spots" lollol

Pay attention to the verb tense, it is imperative, neither in English nor in Spanish the pronoun you (tú) is used in the 2nd person. In all the other personal tenses you do not need to use it in Spanish.

¡Beba agua! (Usted) formal.

¡Bebe agua! (Tú) informal, colloquial.

Bebe más agua, por favor informal, addressed to one person.

Beba más agua, por favor formal, addressed to one person.

Bebé más agua, por favor voseo, addressed to one person.

Bebed más agua, por favor informal, addressed to more than one person.

Beban más agua, por favor formal, addressed to more than one person.