Educational interaction in terms of teaching and learning related coperation is not ubiquitous (cf. Vanderstraeten 2004). Like every kind of face-to-face interaction, it needs to be established among bodily attendant persons who can see and hear each other (cf. Luhmann 1977). The generic problem of establishing cooperation in face-to-face interaction consists of the uncertainty of the attendees concerning the question: who wants to engage with whom in what kind of activity? In opening periods, this problem of situational uncertainty is procesed by giving cues concerning an intended future activity (cf. Gumperz 1992). In this way, the problem of situational uncertainty is transformed into the problem of perfurming and coordinating availability stances.