Mumbling the name part during a rendition of “Happy Birthday”
You’re at a birthday party for a person you only kinda know.
It’s time to sing “Happy Birthday” to them, and you belt out every lyric with gusto, until you get to the part where you sing their name, and you realize you only vaguely remember what the birthday boy or girl’s name is.
So, you mumble something incoherently, hoping your sudden change in volume isn’t too obvious.