This is a great way to do presentations that my awesome mentor, Nina Bonito-Romine shared with me last year. It spares you and your students the pain of sitting quietly and straining to hear 34 separate individual presentations.
Each student should have a presentation prop (a poster or worksheet that they can refer to while they are talking). When you give the cue, everyone gets in groups of two or three students. The students in each group take turns presenting to each other. After enough time has passed for students to be able to all present, tell them to switch groups. You could come up with an orderly manner to do this (á la “One Stay, Two Stray” or “Stand Up/Hand Up/Pair Up” or “Inside/Outside Circles” structures from Kagan CL) or let the students re-group at random. Students then take turns presenting with their new groups. Continue switching until you are done grading presentations.
This is an excellent way to do presentations for two reasons: (1) it takes much less time, and (2) students are speaking much more, as they give their presentation multiple times. Your job as the teacher is to meander through your classroom, observing each student.