The perception of humor, including teasing, with regard to politeness has changed dramatically over the past few decades, as the traditional conceptualization of politeness undertaken in the spirit of linguistic universals has gradually given way to a new understanding inspired by the insights of social theory. This chapter focuses on a particularly aggressive humor type teasing in the context of a Russian foreign language classroom. It addresses a host of interrelated issues: the legitimacy of teasing in educational settings, particularly when instructors and students come from different cultural backgrounds and may not share behavioral norms and expectations, let alone the linguistic means to negotiate such norms. The institutional setting with its inherent imbalance of power between instructors and students also contributes to the gravity of the use of teasing. When humor is deemed inconsequential to the hearers' face/identity, they tend to respond to the literal meaning of the message, adopting the playful mode and playing along with the speakers.