Not sure if we are comparing like with like, but the clearest "breast and necklace" carvings I know of are in Guernsey - see http://www.megalithic.co.uk/article.php?sid=2106157764 and others
You asked if the multi-breasts could be testes - hmm - there is a Greek statue of a deity (can't remember which one) showing very many breasts clustered in rows, but some authorities maintain that they are really testicles! Don't ask me why - looks more like frog spawn to me.
