Marjane enjoys the time she spends with Julie and her mother.
When Julie's mother goes away, Julie throws a party. The parties in Vienna are different to Marjane: "In Iran, at parties, everyone would dance and eat. In Vienna, people preferred to lie around and smoke" (23.42). And by lie around she means in the Biblical sense (translation: naked).
That night holds a few firsts for Marjane: her first time seeing a half-naked man, realizing that Julie is having sex before marriage, and her first contact high.