Here’s a little something I picked up on my travels:
Some hotels have some curious ideas about “double beds” — in fact, they’re often just two single beds shoved together, each with a single-sized duvet. This is fine, unless you and your partner are of the “cuddling” kind. Also, the duvets are often “European” single-size (i.e. totally inadequate, especially for us fat-ass Murkins).
What I always do now, after my first such experience, is pack a queen-sized duvet cover and about eight safety pins. Then, if I find the sleeping arrangements as above, I simply pin the two duvets together to make a larger one, and stuff it into the queen duvet cover with the pin mechanism facing up. Problem solved.
Side note: Safety pins are an essential travel item anyway. Europeans do not know the concept of “safety pins” (at least, they didn’t in Vienna), and trying to explain what a safety pin is and how it works is in your fractured attempt at a furrin language will just lead to puzzled looks. Pack your own.
Google Translate is your friend. The German phrase is “Sicherheitsnadel”. E.g. this Amazon.de listing:
“48 Stück Sicherheitsnadeln Groß, Sicherheitsnadeln Schmuck, Heavy Duty Sicherheitsnadel, Extragroße Robuste Sicherheitsnadelnfür Kleidung,Leder,Segeltuch,Decken,Basteln,Röcke, (4.5/5/6/7cm,Schwarz)”
The design is somewhat different from American, but they clearly work the same way.