It's Marine-Senchou's 17-30th Birthday !!!
After her 3D song concert with P丸様 ( P-marusama ) , they remark how to address each other and how small but big Marine is in certain areas. . .

#hololive #vtuber #houshoumarine

Source:
【重大発表あり!!!】宝鐘マリン生誕祭 3D LIVE！豪華ゲスト＆新曲お披露目！【ホロライブ/宝鐘マリン】
youtube.com/live/NxtHvRVLzXM?si=T5qiBFMIci-3Eh4c