This cut is from Iwatobi Channel ES DJ CD Vol.2! Mamo and tatsu together are like two do-S senpais getting ready to eat up the cute vulnerable koukai (zakki) with hosoyan watching on the sideline...

1:13 even the staff picks on zakki with the script xD and then mamo and tatsu don't miss the chance to make fun of him
2:38 HOMO NAGA KUNNNNN
3:58 crazy (and beautiful) laughter
4:44 hosoyan takes a hit even though he's just sitting on the sideline

thank you to the bilibili user who made this cut from the original cd! video source: http://www.bilibili.com/video/av1783802/