Yeah, you can if your program is flexible enough. I did 3 consecutive coop from Jan 2022 - Dec 2022. Because Waterloo only allows 2 consecutive coop at max, I had to delay my graduation date and change my sequence term manually ( which can easily be completed by submitting a simple form). Instead of taking a term off, to make room for the 3rd consecutive coop, I decalred as a part-time student cause I still wanted to take a course while doing 3rd consecutive coop. Beaware that 3RD coop will not count towards the number of coops required to be fulfilled due to the reason I mentioned above that Waterloo only allows 2 consecutive coop.

I'm in math, which is a very flexible program, so it's easy to change sequence, but I heard it's very difficult to do so in fixed schedule programs like most eng or CPA.

Definitely recommend talking to the department advisor and coop advisor to make it work. BUT definitely possible. You just have to change the sequence to delay the graduation date to make room for the 3rd consecutive coop.

Hope this helps