Cupid hides somewhere on every screen. Find him, then say where he is - and the answer needs a preposition: in, on, under, behind, between.
Prepositions of place are learned from a table and forgotten immediately, because a table gives no reason to choose one. A hidden figure does. Cupid appears somewhere on each screen, the class finds him, and the only way to report the find is with the preposition that fits - behind the sofa, under the table, between the cushions.
Finding him is the fun part and saying it is the lesson, so the answer should always be a full sentence rather than a pointed finger. Two minutes, February-themed, and it works with young learners and with adults who still hesitate between in and on.