When I pocket carry my 642 it rides in a Mika holster. I use the holster because it keeps the gun properly positioned. Without a holster it tends to tilt enough that it's harder to get a good grip.
Never with out a holster,
and never with anything else in the same pocket!
Check your state laws. Unless something has changed recently, in Georgia a gun must be in a holster even if it is in a pocket.
There is an exception for the Barami Hip Grip--that device is actually named in the law.
In addition to covering the trigger, a real and important advantage of a well designed pocket holster is that it holds the gun in a consistent position. It's also far less likely to squirt out of your pocket.