This can't possibly mean "fart" here, can it? I think

This can’t possibly mean “fart” here, can it? I think it has more to do with getting really really drunk, yes?

Agree, it sounds as if they got really plastered.

“Estar pedo” is slang for being drunk

This collection of lessons happens to be very slangish and party-oriented. I suppose it comes in handy for, say, your typical Erasmus student planning to come to Spain.
I persoannly wouldn’t be particularly interested in a Russian version of this for my own learning.