Please see the "notes" section of this U.S. paperback. From the front cover scan, enlarged, it's possible to read the mention of the original title in the small print under "The Day After Tomorrow".
This is quite a good story, although it might currently be viewed as politically incorrect in parts. I hope that the German translator captured, relished, and transferred Heinlein's excitement and philosophy for the benefit of German readers. The German cover art is certainly better and more interesting than the U.S. version linked above.
"The tradition of dancing around the Midsummer pole is an old one, though of course the dances have changed over the centuries. Today organized Swedish Midsummer festivals typically include exhibitions of folk dancing in traditional costumes, as well as ring dances and games for people of all ages to join in. No Midsummer celebration is complete without Små grodorna, a dancing game in which people of all ages hop around the pole while singing about little frogs. The goofiness is part of the fun!"
It does sound interesting. The dancing appears to be more ring or folk than square. (Disclaimer: I'm not an expert on Swedish culture, but the above does seem to pertain to the record.)
Text from B label scan:
Gunnar Lundén-Weldens Orkester
HILDING PETTERSSON lekledare
Potpurri På Svenska Danslekar sammanställt av
Knut Lekare
Sju Vackra Flickor - Viljen I Veta - Jänta Å Ja
Google translate says:
Gunnar Lundén-Weldens Orchestra
HILDING PETTERSSON animators
Potpourri At Swedish dancing games compiled by
Knut Swivels
Seven Beautiful Girls - Will you Know - Lassie A Yes
Lekledare, which translated as "animators", also translates as "games organizer" or "game leader".