How can DBO test other users in OS Auth SQL Server?

Hello! We're using SQL Server OS Auth, and I am DBO. How can I mimic/test another users' experience? When we were on DB Auth in Oracle, it was simple--just access the tables using the user's logon and password. But OS Auth disallows this. I can't test as a regular user, because I am always DBO. What is the workaround?
Thank you!