I’ve always sang that Adams family sing with the line “they’re big & fat & smelly.” If it isn’t that’s the one I’ve taught my daughters anyway
On the subject of atmospheres at Welsh grounds, back when I was a student my uni rugby league team got free tickets for a Wales v Samoa rl World Cup game at the vetch field (we’d played Swansea uni earlier in the day). The place was packed & when they sang “bread of heaven” properly and in tune & not like we normally yell football chants, it really did make the hairs on the back of your neck stand on end
PS Apologies for admitting to both playing & watching rugby league