Place it at the end of a joke segment, just after the laugh track peaks, then follow it with the sad violin as the closing cue. For a sharper cut, put Nelson's ha-ha before it so the contrast makes the shutdown land harder in the edit.
このサウンドについて
This is a brief spoken line, lasting about a second and a half, delivered in a flat, tired voice that sounds done with the joke. It lands as a deadpan shutdown, turning an awkward laugh into an uncomfortable pause and making the room feel suddenly quiet. The dry delivery gives it a blunt, unimpressed feeling that works best when humour has worn thin.