Sideways. Left hand. All cards neatly on top of one another. Fingers and hand covering the cards themselves and keeping them pinned to the felt. Right hand pointing forward and thumb up, acting as a wall. Left thumb peels up all 4 or 5 cards enough to be able to see the right-facing corner of each card all at the same time. That's the pro way.
A little like this, except with far more security.
A few years ago some EPT and I believe Partouche guys ran a brazen af scam where they had 'poker journalists' stand behind players who were too complacent, they literally just texted the guy on the table in real time what he had. He won a bunch of big tournaments that way.