Looking on the internet deeply has found these results:

back to back meeting is the most popular phrase on the web.

back-to-back meeting 147,200 results on the web	back to back meeting 147,700 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
So... yesterday, back back meetings with the sales team. Looks like he had back to to Just a lot going on, back to back meetings.	to to back meetings with the sales team. Just a lot going on, back So... yesterday, back to back meetings. Looks like he had back

back-to-back meeting

147,200 results on the web

back to back meeting

147,700 results on the web

More popular!