I think that "erotic interlude" triggers in our modern minds something much more serious than it would mean back then.
Yes. Perhaps a passionate kiss with some heavy petting?
What happened in that "house on the left?" In "the last Tsarina" it said "they shared an erotic interlude". Alix was a virgin when they married wasn't she?
Not likely that it happened in the house, unless it was a barn, stable, shed or something like that were they sought refuge / privacy. They are not the kind of people who would have rented a room in some sleazy pimp or madam's den. More likely that it happened in the carriage when they passed that house.
BTW the Coburg suburb Ketschendorf (NB Nicholas spells it wrongly) had naughty associations: Although the castle there had been the summer retreat and widow seat of Alix's great great grandmother Duchess Auguste of S-C-G, it had more recently rebuilt by the opera singer Rosine Stoltz, who was a mistress of Alix's grand-uncle Duke Ernst II, who had made her Baroness of Ketschendorf and gave her the castle. Her son Baron Charles of Ketschendorf may have been fathered by Ernst II, although his mother claimed Napoleon III was the father, and he would thus have been Alix's mother's first cousin.
In 1894 the Baroness had sold the castle and it was owned by the Jewish corn merchant and likewise recently ennobled Baron von Mayer.
Schloss Ketschendorf:
