Here's the answer:
“下着も脱いでください”
(shitagi mo nui-de kudasai)
Watch a real native speaker say it:
Here's how it sounds in a textbook:
You could also say:
- 下着も脱いで下さい
Fun fact: the hundreds of thousands of people learning Japanese with Memrise get this phrase correct 95.74% of the time!
