Here's the answer:
“ゆっくりおねがいします”
(yukkuri onegaishimasu)
Watch a real native speaker say it:
Here's how it sounds in a textbook:
You could also say:
- ゆっくりお願いします
Fun fact: the hundreds of thousands of people learning Japanese with Memrise get this phrase correct 90.15% of the time!
