Many believe that a bad dancer is hindered by his legs, and some indecent pranksters inserted the word “eggs” into the proverb. However, it is not. Take a look at two old cartoons:
As you can see, the dancers have eggs on them too, but anything indecent is completely absent! What's the matter?
And the point is in an old European tradition called "Dance with Eggs" or "Egg Dance".
In one version, the dancer had to, without stopping dancing, roll the egg out of the bowl with his foot, and then turn the bowl over so that it covered the egg.
Promotional video:
In another version, a young couple had to dance among eggs scattered on the ground without crushing any of them. If this succeeded, the young were considered betrothed.
It is from here that the saying "Bad dancer gets in the way of eggs." And what those who replaced the eggs with legs in it meant, we do not even guess …