It is a custom for Peruvians, both men and women, to invite you to dinner, a bar, karaoke, disco, etc, order drinks/meals, and expect that the gringo pay. It is cultural that SOME try to take advantage in this way. Some will even invite their own friends who you never met before. Well, why not? It's easy to spend money when it's not your (their) own.
If this happens, only pay your part. Sometimes the fake friends or the business will threaten you, but you are not responsible except for what you ate/drank.
If you can make it for this dates it is highly advisable. Si puedes ir estas fechas es lo mas recomendable.
april 30 to May 2nd
30 de abril al 2 de mayo
it is usually the last weekend in april and/or first week in May
It is LOADS of adventure, sport competitions (white-water rafting, mtn biking, ski-snowboard, rock climbing, etc) , entretainment , cultural dances in the streets, etc because not only there are sport events but the whole town celebrates a religious holiday.
Peruvians are very vocal and strong minded in matters of politics, with rallies becoming quite animated. As a traveler, it's best to steer clear. The many "advertisements" for various politicians are everywhere, even in remote villages.