Whenever you learn a new verb in a foreign language, you should instantly conjugate it and see how many different things you can say. So, with Chupar, you can go through all the different verb endings and see what kinds of wonderful phrases you can come up with for example:
Chupo = I suck
Chupas = you suck
Chupamos = we suck
Chupan = they suck
Chupa = he/she sucks
Always keep in mind too, that all you have to do is say these words with a slight upward inflection at the end and they can all turn into questions.
Chupo? = I suck?
Chupas? = you suck?
Chupamos? = we suck?
Chupan? = they suck?
Chupa? = he/she sucks?
Although you might think that the usefulness of being able to say “you suck” is limited, you’d be wrong…and the reason for that is that Chupar is slang in Peruvian spanish for “to drink.” For example, when people say, “let’s go and drink some beer” they might use the Spanish phrase “vamos a chupar unas chelas” or they might just simply say “vamos a chupar” which literally translates to “lets go suck!”
So, you can imagine the double entendras that are possible and which become perfectly acceptable considering this secondary meaning.
Therefore, when you get to Peru, go up to the first girl you meet and say, “Quieres chuparmelo” and see what happens (she’ll either buy you a beer or do something else…either way it’ll probably be good)!